ToolNestFree Online Mortgage Calculator
Last updated: October 14, 2026
Quick answer: A $400,000 home with 20% down at 6.5% interest over 30 years costs about $2,023 per month in principal and interest — with roughly $408,000 in total interest over the life of the loan. Our free mortgage calculator works out your exact monthly payment, total interest, payoff date, and a year-by-year amortization schedule for any price, down payment, rate, and term — instantly and privately, right in your browser.
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Enter your numbers above, then calculate.
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How to Use the Mortgage Calculator
- Enter the home price and your down payment — the loan amount is the difference.
- Set your annual interest rate and pick a loan term (30, 20, 15, or 10 years).
- Optionally add an extra monthly payment to see how fast you could pay the loan off early.
- Click Calculate Payment for your monthly principal & interest, total interest, payoff date, and the full amortization table.
Why Use Our Mortgage Calculator?
- True monthly payment — principal & interest computed with the standard amortization formula lenders use.
- Year-by-year amortization table — see exactly how each payment splits between principal and interest.
- Extra-payment modeling — add $100–$500/month and watch years of interest disappear.
- Term comparison — switch between 30, 20, 15, and 10-year terms to compare total interest instantly.
- 100% private — every calculation runs locally in your browser; your finances never leave your device.
Common Use Cases
- First-time buyer budgeting: Test home prices against your income with the 28/36 rule — find the price where P&I plus estimated taxes and insurance fits your budget before you tour a single house.
- Refinance decisions: Compare your current payment against a new rate and term: the calculator shows exactly how many months until the interest savings cover the closing costs.
- Extra-payment planning: Model $100, $200, or $500 extra per month and see the payoff date move and total interest drop — the clearest motivation to prepay you'll find.
- Comparing lender offers: Two lenders quote different rates and fees? Run both scenarios side by side — the total-interest figure reveals which offer is actually cheaper over the life of the loan.
- Real-estate investors: Quickly screen rental properties: does the P&I payment leave enough room under expected rent for taxes, insurance, vacancy, and profit?
Mortgage Calculator vs Alternatives
- Bankrate / Zillow mortgage calculators: Brand-name tools with nice sliders — but they're lead-generation funnels: your contact info is the product, and the page pushes you toward partner lenders. Ours asks for nothing and shows the full amortization table they bury.
- Google's mortgage widget: Fast for a ballpark payment right in search results. But it won't show you the year-by-year amortization split or model extra payments — the parts that actually teach you where your money goes.
- Excel's PMT function: =PMT(rate/12, years*12, -loan) gives the exact payment — great inside a bigger financial model. But building the amortization schedule by hand means 360 rows of formulas. The calculator above renders it instantly.
- Your lender's own calculator: Convenient and tied to their current rates — but every lender's calculator is a sales tool tuned to make their offer look good. Run the same numbers here for a neutral second opinion before you sign.
Bottom line: use a lender's calculator to see their offer, and this page to understand it. The amortization table and extra-payment modeling here are the neutral, no-signup version of what the sales funnels won't show you clearly.
Frequently Asked Questions
How is my monthly mortgage payment calculated?
With the standard 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 ÷ 12), and n is the number of payments. Our calculator uses this exact formula, so its principal & interest figure matches what a lender quotes.
Does this include property taxes and insurance?
No — this calculator covers principal and interest (P&I) only. Most homeowners also pay property tax and homeowner's insurance each month, often bundled into escrow (together called PITI). Add your local tax and insurance estimates on top of the P&I figure for your true monthly housing cost.
Is a 15-year or 30-year mortgage better?
It depends on your budget. On a $320,000 loan at 6%, a 30-year term costs about $1,919/month in P&I with roughly $371,000 in total interest; a 15-year term costs about $2,700/month but only about $166,000 in total interest — saving over $200,000. The 15-year builds equity far faster, but the higher payment leaves less room in your budget.
What is amortization, and why is my early payment mostly interest?
Amortization is the gradual payoff schedule of the loan. Because interest is charged on the remaining balance, early payments are interest-heavy: in year one of a $320,000 loan at 6.5%, about $20,695 of your payments goes to interest and only about $3,577 reduces the principal. The split flips as the balance shrinks — check the table above.
What is PMI and when do I pay it?
Private mortgage insurance (PMI) is usually required on conventional loans when your down payment is under 20%. It typically costs 0.5%–1.5% of the loan amount per year, added to your monthly payment, and generally drops off once you reach 20% equity. This calculator's payment figure excludes PMI.
How accurate is this estimate?
The principal & interest math is exact — it is the same formula lenders use, so the P&I payment matches to the cent. Your final quoted payment will differ because of property taxes, insurance, PMI, and closing costs, which vary by location and lender. Use this as a planning figure and confirm with a lender's Loan Estimate.
How much house can I afford?
Lenders use the 28/36 rule: spend no more than 28% of gross monthly income on housing (PITI) and no more than 36% on all debt. At $8,000/month income, that's up to ~$2,240/month for housing. Plug that payment into the calculator above and adjust the home price until the P&I fits — then add taxes and insurance on top.
Why is 20% down the magic number?
Two reasons: at 20% down you avoid PMI on conventional loans (saving 0.5–1.5% of the loan amount per year), and you start with real equity, which protects you if prices dip. Below 20% isn't disqualifying — FHA loans allow 3.5% down — but you'll pay PMI until you reach 20% equity.
How much do extra monthly payments actually save?
A lot. On a $320,000 loan at 6.5% over 30 years, adding $200/month to the ~$2,023 payment pays the loan off in about 23.5 years instead of 30 — roughly 6.5 years early and ~$105,000 less in total interest. Try it in the calculator's extra-payment field and watch the amortization table shrink.
What credit score do I need for a mortgage?
Conventional loans generally want 620+; FHA loans go down to 580 with 3.5% down (500 with 10% down). But the best rates typically require 740+ — a borrower at 740 can pay meaningfully less interest than one at 660 on the same loan, which is why rate-shopping after a score check matters.
Fixed-rate or adjustable-rate (ARM) — which is better?
A 30-year fixed rate never changes: predictable, usually the right call if you'll stay 7+ years. A 5/1 ARM starts ~0.5–1% lower but adjusts after 5 years — it can win if you'll sell or refinance before the adjustment. Compare both with the calculator: run your scenario at each rate and weigh the monthly savings against the reset risk.
What are closing costs?
The fees to finalize the loan — origination, appraisal, title insurance, prepaid taxes/insurance — typically 2–5% of the loan amount ($6,400–$16,000 on a $320,000 loan). They're due at closing on top of your down payment, and your lender must itemize them on the Loan Estimate at least 3 business days before closing.