Estimate monthly mortgage payment, rental cash flow, net operating income, cap rate, cash-on-cash return, and total annual ROI for investment properties in USA and UK formats.
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Whether you are buying your first home, investing in rental property, refinancing an existing mortgage, or simply trying to decide whether renting or buying makes more financial sense right now — our free real estate calculators give you fast, accurate answers. This page covers every major property calculation in one place, with clear formulas, real-world examples, and country-specific guidance for the USA, UK, and Europe.
Real estate transactions are among the largest financial decisions most people ever make. Getting the numbers right before you commit can mean the difference between a smart investment and an expensive mistake. Use the sections below to find the calculator you need, understand how it works, and interpret what the results actually mean for your situation.
A real estate calculator is an online tool that runs the financial numbers behind buying, selling, renting, or investing in property — without needing a spreadsheet or financial adviser every time you want a quick estimate. These calculators range from simple mortgage payment estimators to sophisticated investment analysis tools that factor in rental income, vacancy rates, operating expenses, and long-term appreciation.
The most commonly used real estate calculators include:
The mortgage calculator is the most widely used real estate tool online. A mortgage payment is typically the single largest monthly expense a homeowner carries, and understanding it before you sign is essential.
A basic mortgage calculator takes four inputs: the loan amount (purchase price minus your down payment or deposit), the annual interest rate, the loan term in years, and the payment frequency. From these it calculates your monthly principal-and-interest payment using a standard amortization formula.
| Variable | What It Means |
|---|---|
| M | Monthly payment (what you want to find) |
| P | Principal — total amount borrowed |
| r | Monthly interest rate (annual rate ÷ 12) |
| n | Total number of payments (years × 12) |
Monthly Mortgage Payment Formula:
M = P × [r(1 + r)^n] ÷ [(1 + r)^n − 1]
More advanced mortgage calculators also factor in property taxes, homeowners or buildings insurance, Private Mortgage Insurance (PMI) in the US when the down payment is below 20%, HOA fees for condos, and the effect of extra monthly payments on your total interest cost and payoff date.
| Input | Value |
|---|---|
| Home price | $400,000 |
| Down payment | 20% ($80,000) |
| Loan amount | $320,000 |
| Interest rate | 6.8% (30-year fixed) |
| Estimated monthly payment (P&I only) | ~$2,147 |
| Input | Value |
|---|---|
| Property price | £280,000 |
| Deposit | 10% (£28,000) |
| Loan amount | £252,000 |
| Interest rate | 5.1% (2-year fixed) |
| Mortgage term | 25 years |
| Estimated monthly repayment (capital & interest) | ~£1,310 |
In the United States, the 30-year fixed-rate mortgage is the dominant product, accounting for roughly 70–90% of all home loans. Rates are quoted as APR, and borrowers can choose from conventional, FHA, VA, and jumbo loan products depending on their situation.
In the UK, most mortgages are fixed for a shorter introductory period — typically 2 or 5 years — before reverting to the lender's Standard Variable Rate (SVR). Borrowers regularly remortgage when their fixed period ends to avoid the higher SVR. The Bank of England base rate directly influences tracker and SVR mortgages, meaning UK homeowners on variable deals are more exposed to rate changes than Americans on a long-term fixed product.
In Europe, practices vary widely. Germany favours long fixed-rate periods of 10–15 years. France has a strong tradition of fixed-rate lending with strict affordability rules set by the Haut Conseil de Stabilité Financière. The Netherlands and Belgium have their own rate structures and LTV norms. Always use a country-specific calculator when modelling European mortgage costs.
Use our Mortgage Calculator for US scenarios and our UK Mortgage Calculator for British buyers, which uses pence-accurate calculations aligned to current Bank of England rate benchmarks.
Knowing your estimated monthly payment is only half the picture. The other half is understanding how much a lender will actually offer you — which depends on your income, existing debt, credit history, and the lender's affordability criteria.
Most US lenders apply the 28/36 rule: your total monthly housing costs (mortgage, taxes, insurance) should not exceed 28% of your gross monthly income, and your total debt obligations including housing, car loans, student debt, and credit cards should not exceed 36%. Government-backed loans such as FHA loans may permit higher ratios.
Simple Affordability Formula:
Max monthly housing payment = Gross monthly income × 0.28
UK lenders typically use income multiples as a starting point — usually 4 to 4.5 times your annual gross salary. Most also run an affordability stress test to confirm you could still afford repayments if interest rates rose by a further 2–3 percentage points. As a rough guide, a household earning £60,000 per year might be offered a mortgage of up to £270,000, subject to their full financial profile and the lender's specific criteria.
Use our Mortgage Affordability Calculator to get a personalised estimate based on your income, monthly outgoings, and current rate conditions.
Amortization is the process of repaying a loan through regular scheduled payments, with each payment split between interest and principal. In the early years of a mortgage, the bulk of each payment goes toward interest. Over time, as your outstanding balance falls, the proportion going to principal increases.
For homeowners, understanding amortization helps you see exactly how much equity you are building each month. For property investors, it affects your cash flow projections and — in the US — your deductible interest expenses. Knowing your amortization schedule also helps you calculate the financial benefit of making extra principal payments.
Amortization Split Formula (Any Given Month):
Monthly interest = Outstanding balance × monthly rate
Monthly principal = Monthly payment − Monthly interest
New balance = Previous balance − Monthly principal
Adding even a modest extra payment to your mortgage principal each month can dramatically reduce your total interest cost and shorten your loan term. On a $300,000 loan at 7% over 30 years, paying an extra $200 per month could save over $60,000 in interest and cut nearly 6 years off the loan. Our Amortization Calculator generates a full year-by-year payment schedule and shows exactly how extra payments change your payoff date and total interest.
If you are evaluating a rental property as an investment, the capitalization rate — commonly called the cap rate — is one of the first numbers you need. It measures the property's annual net income yield independently of how you are financing it, making it ideal for comparing investment properties on equal footing.
Cap Rate = (Net Operating Income ÷ Property Value) × 100
Net Operating Income (NOI) = Gross annual rent − Annual operating expenses
Operating expenses include property management fees, insurance, maintenance, property taxes, and a vacancy allowance. They do not include mortgage payments — cap rate is a financing-agnostic metric.
| Item | Annual Amount |
|---|---|
| Gross rental income | $24,000 |
| Vacancy loss (5%) | −$1,200 |
| Property management (10%) | −$2,280 |
| Insurance and property taxes | −$3,500 |
| Maintenance and repairs | −$1,800 |
| Net Operating Income (NOI) | $15,220 |
| Property purchase price | $220,000 |
| Cap Rate | 6.9% |
There is no universal good cap rate — it depends entirely on the market and your investment strategy. In prime urban markets like New York City, San Francisco, London, or Paris, cap rates of 3–5% are common because property values are high and long-term appreciation potential is strong. In secondary or tertiary markets across the US Midwest, the North of England, or parts of Central Europe, cap rates of 6–10% are achievable, though these typically carry higher risk or reflect weaker appreciation prospects.
| Market Type | Typical Cap Rate Range | Notes |
|---|---|---|
| Prime US gateway cities (NYC, LA, SF) | 3.0–5.0% | High appreciation, lower income yield |
| Secondary US markets (Midwest, Southeast) | 6.0–10.0% | Better cash flow, lower appreciation |
| London (Zones 2–3) | 3.5–5.0% | Strong demand, constrained supply |
| UK regional cities (Manchester, Liverpool, Leeds) | 5.5–9.0% | Higher yields, growing demand |
| Western Europe (Paris, Amsterdam, Berlin) | 3.0–5.5% | Regulated markets, steady appreciation |
Use our Cap Rate Calculator to instantly compute the capitalization rate for any property you are evaluating.
Rental yield is the metric most commonly used in the UK and Europe to compare investment properties. It measures annual rental income as a percentage of the property's purchase price and comes in two forms: gross and net.
Gross Yield = (Annual Rent ÷ Purchase Price) × 100
Example: £12,000 annual rent on a £180,000 property = 6.67% gross yield.
Net Yield = ((Annual Rent − Annual Costs) ÷ Purchase Price) × 100
Annual costs include property management fees, lettings agent fees, landlord insurance, maintenance reserves, and an allowance for void periods. Net yield is always the more meaningful number for investment decisions — gross yield is just a quick comparison tool.
| City | Average Gross Yield | Notes |
|---|---|---|
| Liverpool | 7.0–9.0% | Among the UK's highest yielding cities |
| Manchester | 6.5–8.5% | Strong student and professional demand |
| Birmingham | 6.0–8.0% | Major regeneration underway |
| Leeds | 5.5–7.5% | Growing tech and financial services hub |
| Edinburgh | 5.0–7.0% | Short-term let regulation affecting supply |
| London (Zone 2–3) | 3.5–5.0% | Lower yield, higher long-term appreciation |
Calculate gross and net rental yield instantly with our Rental Yield Calculator.
Return on Investment (ROI) in real estate captures the full picture: rental income, property appreciation, mortgage pay-down, and the effects of leverage. For property investors, ROI is ultimately the number that tells you whether a deal was worth making.
Cash-on-Cash Return = (Annual Pre-Tax Cash Flow ÷ Total Cash Invested) × 100
Annual pre-tax cash flow = NOI − Annual mortgage payments
Total cash invested = Down payment + closing costs + initial repairs
| Item | Amount |
|---|---|
| Purchase price | $180,000 |
| Down payment (25%) | $45,000 |
| Closing costs | $4,500 |
| Initial repairs and setup | $3,000 |
| Total cash invested | $52,500 |
| Annual NOI (after all operating expenses) | $11,400 |
| Annual mortgage payments | $8,730 |
| Annual pre-tax cash flow | $2,670 |
| Cash-on-Cash ROI | 5.09% |
That 5.09% cash-on-cash return does not include property appreciation or mortgage equity pay-down. If the property gained 4% in value that year, the total blended return would be considerably higher. Many investors find that over a 10-year hold, appreciation and equity build-up contribute more to total ROI than monthly cash flow does.
Run your own numbers with our ROI Calculator, which factors in all income, expenses, financing, and appreciation assumptions together.
Closing costs are one of the biggest surprises for first-time buyers. Most people focus entirely on their deposit or down payment and then discover they need thousands in additional cash at closing or completion. Calculating these upfront prevents last-minute shortfalls.
In the United States, closing costs typically run between 2% and 5% of the loan amount. On a $350,000 purchase with a 10% down payment, that is roughly $6,300 to $15,750 on top of the $35,000 deposit. Common items include loan origination fees, appraisal fees, title insurance, attorney fees in some states, prepaid homeowners insurance, prepaid property taxes, and recording fees.
In England and Northern Ireland, buyers pay Stamp Duty Land Tax (SDLT) on residential property purchases. The rates below apply to standard purchases. First-time buyers receive relief on properties up to £625,000. Additional property purchases attract a 3% surcharge on top of the standard rates.
| Property Value Band | SDLT Rate (Standard) | Additional Property Rate |
|---|---|---|
| Up to £250,000 | 0% | 3% |
| £250,001 – £925,000 | 5% | 8% |
| £925,001 – £1,500,000 | 10% | 13% |
| Over £1,500,000 | 12% | 15% |
Scotland applies Land and Buildings Transaction Tax (LBTT) and Wales charges Land Transaction Tax (LTT), both with their own rate structures. Always check the specific rates for the country within the UK where you are buying.
European property purchase costs vary considerably by country. France adds notary fees and transfer taxes that typically total 7–8% of the purchase price on existing properties. Germany combines real estate transfer tax of 3.5–6.5% depending on the state, notary fees of around 1.5%, and land registry fees of approximately 0.5%. Spain typically adds 6–10% in taxes and fees depending on the region and whether the property is new or existing. Always budget for these before evaluating any European property deal.
Estimate your total purchase costs including stamp duty with our Closing Cost Calculator.
The rent-versus-buy question is one of the most debated in personal finance. The honest answer is that it depends on your local market, your intended length of stay, your financial situation, and your personal priorities. A good calculator removes the emotion and shows you the numbers clearly.
The widely referenced 5-year rule holds that buying generally makes more financial sense if you plan to stay in the property for at least 5 years. This is because transaction costs — stamp duty, solicitor fees, agent commissions, survey costs — are high enough that they take several years of ownership benefits to recoup. In high-cost markets like London, New York, or San Francisco, the breakeven point can stretch to 7–10 years. In more affordable markets it can be as short as 2–3 years.
Model your own rent vs buy breakeven point with our Rent vs Buy Calculator.
Home equity is the portion of your property's value that you actually own outright — the current market value minus any outstanding mortgage balance. As you pay down your mortgage and as property values rise, your equity grows. This equity is a real financial asset you can borrow against through a Home Equity Loan or Home Equity Line of Credit (HELOC) in the US, or through remortgaging in the UK.
Home Equity Formula:
Home Equity = Current Property Value − Outstanding Mortgage Balance
Loan-to-Value (LTV) = Outstanding Balance ÷ Property Value × 100
Example: A property worth £320,000 with a £185,000 outstanding mortgage = £135,000 equity and a 57.8% LTV. Most UK lenders offer their best remortgage rates at LTV thresholds of 60%, 75%, and 80%, so tracking your LTV as you pay down your loan is financially worthwhile.
Track your equity position and LTV ratio with our Home Equity Calculator.
Refinancing in the US (called remortgaging in the UK) means replacing your current mortgage with a new one — typically to access a lower interest rate, change the loan term, or release equity. It can save significant money over the life of a loan, but upfront costs must be recouped before you come out ahead.
The key question in any refinancing decision is how long it takes to recoup the switching costs through your monthly payment savings. If refinancing costs $4,000 and saves you $200 per month, you break even in 20 months. If you plan to stay in the property longer than that, refinancing is likely worth it.
Refinance Break-Even Formula:
Break-Even (months) = Closing Costs ÷ Monthly Payment Savings
Use our Refinance Calculator to model your specific scenario, compare your current rate against a new rate, and calculate exactly when you would start saving money.
If you are buying your first home, calculators help you understand what you can genuinely afford — beyond the figure a lender is willing to offer. Start with the affordability calculator to set a realistic budget, then use the mortgage calculator to understand monthly payments, and the closing cost calculator to make sure you will not be short on cash at completion or closing.
Investors need cap rate, rental yield, cash-on-cash ROI, and amortization calculators as core analytical tools. Running these numbers before making an offer separates profitable deals from money-losing ones. They also prevent the emotional decision-making that costs investors dearly — especially when a property looks attractive on surface-level gross yield but falls apart once real operating costs are factored in.
Understanding your current equity position, estimating net proceeds after estate agent or realtor fees and mortgage payoff, and calculating potential Capital Gains Tax liability all require reliable calculations before you put your home on the market.
The rent vs buy calculator is specifically designed for people at this decision point. It brings together savings, income, local property prices, and appreciation assumptions to show whether renting or buying makes more sense given your specific circumstances and local market conditions.
Anyone mid-mortgage should periodically run a refinance or remortgage analysis, particularly when fixed-rate periods end. If rates have moved significantly since you took out your loan, or if your improved financial profile qualifies you for better LTV rates, switching could save you thousands over your remaining term.
Many new investors calculate ROI or cap rate using gross rental income rather than net operating income. Ignoring property management fees (typically 8–12% of rent), maintenance reserves, insurance, taxes, and vacancy periods can make a marginal investment look highly attractive — until the real costs arrive. Always use NOI, not gross rent, for investment analysis.
First-time buyers routinely underestimate total purchase costs. UK buyers sometimes focus entirely on the deposit and overlook solicitor fees, survey costs, and stamp duty. US buyers similarly may not budget for 2–5% in closing costs on top of their down payment. These figures need to be included in your total cash required and your ROI calculations.
Even in strong rental markets, properties experience void periods. A conservative vacancy allowance of 5–10% of gross rent should be built into every rental property analysis. Assuming 100% occupancy consistently leads to inflated income projections.
Cap rate assumes a cash purchase and ignores financing costs entirely. Cash-on-cash return measures what you actually earn on your invested cash, accounting for your mortgage payments. Both metrics are useful but they answer different questions. Treating them as interchangeable leads to seriously flawed investment comparisons.
In the UK particularly, buyers on short-term fixed or tracker rate mortgages need to test their affordability if rates rise. A 1% increase on a £250,000 mortgage adds roughly £130–£140 to monthly repayments. Our UK Mortgage Calculator includes rate sensitivity testing for exactly this purpose.
In the US, investment property profits are subject to capital gains tax — at lower long-term rates for assets held over a year, with a potential 1031 exchange option to defer taxes. In the UK, residential landlords pay Capital Gains Tax at 18% or 24% (depending on income tax band) above the annual exempt amount. Failing to model exit costs often makes investments look more profitable than they really are.
A property with a 9% gross yield in a high-vacancy market may deliver a worse net return than a property with 6% gross yield in a stable, low-maintenance location. Always compare net yield and factor in location quality, tenant demand, and long-term appreciation prospects alongside the income figure.
Your calculated monthly payment is a baseline estimate for budgeting. Lenders will also consider your total PITI and compare it to your gross income. Most want total housing costs below 28–31% of gross monthly income. Use the result as an anchor for your budget, not a guarantee of what you will be approved for — your credit score, deposit size, and existing debts all influence the final offer.
A calculated cap rate or yield is only as good as the assumptions you enter. Income projections and expense estimates can easily be optimistic. Always cross-check your rent assumptions against comparable rental listings in the actual street or postcode, and apply conservative vacancy and maintenance allowances — especially for older properties.
ROI calculations become most valuable when compared — to alternative properties, to other asset classes, and to your own risk profile. A 5% cash-on-cash return looks very different if prevailing savings rates are 4.5% versus 1%. Context matters as much as the absolute number. Always consider the total return including appreciation, not just the annual cash flow yield.
The rent vs buy calculation is highly sensitive to the assumed annual property appreciation rate. Small differences — say 2% versus 4% per year — can flip the result significantly over a 10-year horizon. Run the calculation across a range of appreciation scenarios to understand the full range of possible outcomes rather than relying on a single optimistic figure.
Real estate decisions rarely involve just one calculation. These related tools on FreeUSUKCalculator.com will help you build a complete financial picture before you commit:
A real estate calculator helps you estimate the financial figures involved in buying, selling, renting, or investing in property. Common uses include calculating monthly mortgage payments, working out the ROI on a rental property, estimating stamp duty or closing costs, comparing the financial cost of renting versus buying, and analysing investment metrics like cap rate and rental yield. These tools are useful for first-time buyers, experienced investors, landlords, and anyone comparing property options before making a decision.
Your monthly mortgage payment is calculated using the amortization formula: M = P × [r(1 + r)^n] ÷ [(1 + r)^n − 1], where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the total number of payments (loan term in years multiplied by 12). On a $300,000 loan at 6.8% interest over 30 years, the monthly principal and interest payment is approximately $1,960. Use our Mortgage Calculator to get an instant result without doing the maths manually.
A good cap rate depends entirely on your market. In high-cost urban markets like New York or London, cap rates of 3–5% are typical. In secondary markets across the US Midwest or UK cities like Manchester and Liverpool, cap rates of 6–10% are achievable. Most experienced investors look for a cap rate comfortably above their financing interest rate — otherwise the investment relies entirely on appreciation to generate a return on leveraged capital.
Both cap rate and rental yield measure property income as a percentage of value, but differ in detail. Cap rate uses net operating income — rent minus all operating expenses, but before mortgage costs — divided by property value. Rental yield typically refers to gross rent divided by purchase price. Cap rate is the standard investment analysis metric in the US. Gross rental yield is the most common quick-comparison figure in the UK. Net rental yield (income minus costs divided by price) is the most accurate for real investment decisions in any market.
The traditional guideline is that no more than 30% of your gross monthly income should go toward rent or housing costs. This is known as the 30% rule. In high-cost cities like London, New York, or Amsterdam, many renters spend 35–45% of income on rent due to market conditions. A more practical approach is to ensure you can still save adequately — ideally 15–20% of income — and cover all essentials comfortably after paying rent. Our Rent vs Buy Calculator can help you see whether buying might be more cost-effective in your specific area.
For a leveraged rental property purchased with a mortgage, the most practical ROI metric is cash-on-cash return: Annual Cash Flow ÷ Total Cash Invested × 100. Annual cash flow is your net operating income minus all mortgage payments. Total cash invested is your down payment plus closing costs plus any initial renovation costs. Always use net income — after vacancy, management fees, insurance, taxes, and maintenance — not gross rent. Our ROI Calculator handles all these variables automatically.
In the United States, closing costs typically range from 2% to 5% of the loan amount. On a $300,000 purchase with a $270,000 loan, expect to pay $5,400 to $13,500 in closing costs. These include loan origination fees, appraisal fees, title insurance, attorney fees in some states, prepaid homeowners insurance, prepaid property taxes, and recording fees. Our Closing Cost Calculator provides a detailed estimate for your specific purchase.
In the UK, a gross rental yield of 5–8% is generally considered good for a buy-to-let property. Northern cities like Liverpool, Manchester, and Leeds regularly offer yields in the 6–9% range. London yields are typically 3.5–5% due to proportionally higher purchase prices, though long-term appreciation has historically compensated. After accounting for management fees, void periods, insurance, and maintenance, net yields are usually 1–2 percentage points below gross figures. Always calculate net yield before making a buy-to-let investment decision.
A 30-year mortgage offers lower monthly payments but costs significantly more in total interest over the life of the loan. A 15-year mortgage requires higher monthly payments but typically saves tens of thousands in interest and builds equity much faster. On a $300,000 loan, the difference in total interest paid over the full term can exceed $100,000. If you can comfortably afford the higher monthly payment without straining your budget, the 15-year mortgage almost always wins mathematically. Use our Mortgage Calculator to compare both scenarios side by side.
Amortization is the process of paying off a mortgage through regular scheduled payments where each payment covers the interest owed on the current balance with the remainder reducing the principal. In the early years of a loan, most of each payment goes toward interest. Over time, as the balance falls, more goes toward principal. On a $250,000 loan at 7% over 30 years, your first payment of roughly $1,663 might include about $1,458 in interest and only $205 in principal. By year 25 the split reverses sharply. Our Amortization Calculator shows this progression payment by payment.
There is no single answer — it depends on your location, intended length of stay, deposit size, and personal priorities. In most UK markets, buying becomes more financially advantageous after 5–7 years when transaction costs are recouped and equity build-up adds up. In London and other high-cost areas the breakeven point can be longer due to larger stamp duty bills and higher deposit requirements. Renting preserves flexibility and liquidity, which has real value for people whose lives or careers may require moving. Our Rent vs Buy Calculator models the full comparison using your actual numbers.
Most UK lenders require a minimum deposit of 5–10% for residential mortgages, though rates improve significantly at LTV thresholds of 85%, 80%, 75%, and 60%. For buy-to-let properties, most lenders require at least 25% deposit. A larger deposit means lower monthly repayments, access to better interest rates, and no need for mortgage insurance equivalents. First-time buyers may benefit from government schemes and Lifetime ISA bonuses to help build a deposit more quickly.
Real estate is an area where the numbers genuinely matter. A half-percentage-point difference in mortgage rate, an optimistic vacancy assumption, or an overlooked stamp duty bill can turn what appears to be a strong financial decision into a costly one. The calculators on FreeUSUKCalculator.com are designed to remove the guesswork and give you fast, accurate figures — whether you are based in the United States, the United Kingdom, or anywhere across Europe.
Whether you are calculating a mortgage payment for the first time, stress-testing an investment property's return, weighing a 15-year against a 30-year loan, or finally running the numbers on a rent vs buy decision you have been putting off — start with the right tool and build your decision on solid ground.
Bookmark this page and return whenever your property situation changes. Markets move, rates shift, and the best financial decisions come from people who keep running the numbers.
Disclaimer: All calculators and content on FreeUSUKCalculator.com are provided for educational and informational purposes only. Results are estimates based on the inputs you provide and standard mathematical formulas. They do not constitute financial, investment, mortgage, legal, or tax advice. Property values, interest rates, stamp duty rates, tax rules, and regulations change frequently and vary significantly by location and individual circumstances. Always consult a qualified financial adviser, mortgage broker, solicitor, chartered surveyor, or tax professional before making any property-related financial decision. Stamp duty and transaction cost information is provided as general guidance and may not reflect the most current legislation in your jurisdiction.
Results are estimates only and are not financial, tax, legal, or investment advice. Real property returns depend on financing terms, maintenance surprises, local laws, tenant quality, taxes, and market conditions. Review all property decisions with qualified professionals.
It estimates the financial performance of a property — cash flow, return on investment, cap rate and total return — from the purchase price, financing, rental income and operating expenses.
Capitalization rate is net operating income ÷ property price. Typical rates run about 4-10% depending on location and risk; higher cap rates mean more income relative to price but often more risk.
It is annual pre-tax cash flow divided by the actual cash you invested (deposit, closing costs, repairs). It shows the real yield on the money you put in, accounting for the mortgage.
Beyond the mortgage, include property tax, insurance, maintenance, management fees, vacancy allowance and repairs. Leaving these out makes a deal look more profitable than it is.