What the Real Estate Calculator does
This real estate calculator takes a property value, a down payment percentage, a loan term, and an interest rate, then returns the loan amount and the monthly principal-and- interest payment using the standard fully amortising mortgage formula. It is designed for quick affordability checks and for comparing two or three financing scenarios side by side.
Real-world monthly outflow is higher than principal and interest alone — property taxes, homeowners insurance, mortgage insurance, and HOA dues all sit on top. The sections below explain how to translate the calculator's output into a complete PITI estimate and how to think about closing costs, refinancing, and the rent-vs-buy decision.
How to use the Real Estate Calculator
Enter the home's purchase price as the property value, the down payment as a percentage (20 means 20%), the loan term in years (typically 30 or 15), and the annual interest rate as a percentage (6.5 means 6.5%). The calculator subtracts the down payment to compute the loan amount, converts the annual rate to a monthly rate, and amortises over the total number of months.
For an apples-to-apples comparison between offers, hold the loan term and home price constant and vary the down payment and rate. For a refinance scenario, use the remaining balance as the property value and set the down payment to 0%.
PITI: the four parts of a payment
Lenders underwrite to PITI — Principal, Interest, Taxes, and Insurance — not to principal and interest alone. The principal and interest piece is what this calculator returns; taxes and insurance are typically escrowed monthly and paid by the lender on your behalf. Add HOA and PMI separately when they apply.
PITI = Principal + Interest + Taxes/12 + Insurance/12
(+ PMI/12 if down payment < 20%)
(+ HOA if condo or planned community)The table below shows estimated monthly PITI for a $400,000 home at three down-payment levels, all at a 7.00% rate over 30 years. Taxes are estimated at 1.0% of value per year, insurance at $1,500 per year, and PMI at 0.6% of the loan balance per year when the down payment is below 20%.
| Down % | Loan | P&I | Tax | Ins | PMI | PITI |
|---|---|---|---|---|---|---|
| 20% | $320,000 | $2,129 | $333 | $125 | $0 | $2,587 |
| 10% | $360,000 | $2,395 | $333 | $125 | $180 | $3,033 |
| 5% | $380,000 | $2,528 | $333 | $125 | $190 | $3,176 |
Note that dropping the down payment from 20% to 5% adds about $590 a month even at the same interest rate, with PMI accounting for roughly a third of the increase.
Real Estate Calculator worked example
A buyer is considering a $450,000 home with a 20% down payment on a 30-year fixed mortgage at 6.75%. The calculator handles the principal and interest; we will then layer on taxes and insurance to estimate full PITI.
Inputs Home price = $450,000 Down payment 20% = $90,000 Loan amount L = $360,000 Annual rate = 6.75% → monthly r = 0.005625 Term = 30 yrs → n = 360 months Monthly P&I (amortisation formula) M = L × r × (1 + r)^n / ((1 + r)^n - 1) M = 360,000 × 0.005625 × 1.005625^360 / (1.005625^360 - 1) M ≈ $2,335 Add taxes & insurance (escrow) Property tax (≈ 0.89% / yr) → $4,000 / 12 = $333 Homeowners insurance → $1,500 / 12 = $125 PMI (down ≥ 20%) → $0 Estimated monthly PITI $2,335 + $333 + $125 + $0 ≈ $2,793
Total interest paid over the full 30 years is about $480,000 — more than the original loan — which is why even a modest rate reduction at refinance time can save tens of thousands.
Down payment and PMI
Putting 20% down on a conventional loan eliminates private mortgage insurance, which typically costs 0.3–1.5% of the loan balance per year. Smaller down payments remain widely available — FHA at 3.5%, conventional 97 at 3%, VA and USDA at 0% for eligible buyers — but each has its own mortgage-insurance or funding-fee structure.
PMI on a conventional loan can usually be cancelled once the loan-to-value ratio reaches 80% (by paydown or appraisal), and it auto-terminates at 78%. FHA mortgage insurance, by contrast, generally lasts the life of the loan unless you refinance into a conventional mortgage.
Closing costs
Closing costs are one-time fees paid at settlement, typically ranging from 2% to 5% of the purchase price for buyers in the United States. They cover the lender, the title company, the appraiser, government recording, and prepaid items that fund the initial escrow account. A representative break-down for a $400,000 home with a $320,000 loan looks like this:
| Item | Typical cost | % of price |
|---|---|---|
| Loan origination fee | $1,600 – $3,200 | 0.5 – 1.0% |
| Appraisal | $500 – $700 | ≈ 0.15% |
| Title insurance (lender + owner) | $1,500 – $2,500 | 0.4 – 0.6% |
| Other lender fees (underwriting, processing) | $800 – $1,500 | 0.2 – 0.4% |
| Recording & transfer tax | $500 – $4,000 | varies by state |
| Prepaid property taxes (escrow) | $1,000 – $3,000 | 0.25 – 0.75% |
| Prepaid homeowners insurance | $1,200 – $2,000 | 0.3 – 0.5% |
| Total (typical) | $8,000 – $20,000 | 2 – 5% |
On a refinance, closing costs are usually 2–3% of the loan balance because there is no transfer tax and no owner's title policy. Lenders may offer "no-cost" refinances by rolling fees into the rate; compare the lifetime cost rather than just the monthly payment.
Rent vs buy
The right answer depends on time horizon, local price-to-rent ratio, expected appreciation, and the opportunity cost of the down payment. A useful starting heuristic is the 5-year rule: combined transaction costs (≈ 8–10% when buying and selling) typically take five years of equity build-up and appreciation to recover.
Annual cost of ownership (rough) = PITI × 12 + maintenance (≈ 1% of home value / yr) + HOA (if any) + opportunity cost (down payment × expected return) − tax benefit (mortgage interest + property tax, if itemising) − expected appreciation × home value Compare against Annual rent for an equivalent home
When the resulting ownership cost is lower than annual rent and you plan to stay put for five-plus years, buying usually wins. When ownership cost is higher and your time horizon is short, renting and investing the would-be down payment elsewhere is frequently the stronger move.
When to refinance
Refinancing replaces the existing mortgage with a new one, ideally at a better rate, a different term, or to extract equity. The break-even calculation tells you whether the move pays off:
Break-even months = closing costs / monthly savings Example Old payment (P&I) = $2,335 New payment at 5.50% = $2,044 Monthly savings = $291 Refi closing costs = $4,500 Break-even = 4,500 / 291 ≈ 15.5 months
Refinance when you can drop the rate by at least 0.75–1.00 percentage point and you plan to stay long enough to clear break-even. Other valid reasons include shortening to a 15-year term, removing PMI after reaching 20% equity, switching from an adjustable-rate to a fixed-rate loan, or pulling cash out for a large project at a lower rate than alternative financing.
Real Estate Calculator FAQ
- How much should I put down on a house?
- The conventional benchmark is 20% of the purchase price, because that level avoids private mortgage insurance (PMI) on conventional loans and lowers the monthly payment. Smaller down payments are common — FHA loans go as low as 3.5% and conventional 97 loans as low as 3% — but expect PMI, a higher rate, and a larger principal balance until you reach roughly 20% equity.
- What does PITI stand for?
- PITI is the four components of a typical monthly housing payment: Principal (loan paydown), Interest (cost of borrowing), Taxes (property tax escrow), and Insurance (homeowners insurance escrow). Lenders use PITI rather than principal-and-interest alone when underwriting, because taxes and insurance are unavoidable carrying costs. Add HOA dues and PMI separately when they apply.
- How much are closing costs?
- Buyer closing costs typically run 2–5% of the purchase price in the United States, covering lender origination, appraisal, title insurance, recording fees, and prepaid taxes and insurance. On a $400,000 home that is roughly $8,000–$20,000. The exact number varies by state, lender, and whether the seller agrees to credit any closing costs at the negotiation stage.
- How do I decide whether to rent or buy?
- Compare the all-in cost of ownership (PITI plus maintenance, HOA, and opportunity cost on the down payment) against rent for a comparable home, then factor in how long you will stay. Below roughly five years the transaction costs of buying and selling — about 8–10% combined — usually outweigh equity build-up. The longer you stay and the faster local prices appreciate, the more buying favours the buyer.
- What is a good cap rate for rental property?
- Capitalisation rate equals net operating income divided by purchase price, expressed as a percentage. Stabilised rentals in primary US markets typically trade at 4–7% cap rates, secondary markets 6–9%, and value-add or tertiary markets above 9%. A higher cap rate means more income per dollar invested but usually signals more risk, more management, or weaker appreciation.
- What is DSCR and why does it matter for investment loans?
- Debt Service Coverage Ratio is the property's net operating income divided by its annual mortgage payment. Most DSCR lenders require 1.20–1.25 minimum, meaning the rental income must exceed the debt service by at least 20–25%. DSCR loans qualify the property rather than the borrower's W-2 income, which is why investors with multiple rentals often prefer them.
- When does it make sense to refinance?
- The rule of thumb is to refinance when you can drop the interest rate by at least 0.75–1.00 percentage point and stay in the home long enough to recover the closing costs — break-even is closing costs divided by monthly savings. Cash-out refinances, removing PMI after reaching 20% equity, or shortening the term to a 15-year loan are also common reasons even without a rate drop.