Free Mortgage Calculator
Calculate your monthly mortgage payment, total interest cost, and full amortisation schedule. Enter your home price, down payment, interest rate, and loan term. Free, private — all calculations run in your browser.
📊 Scenario Comparison
| Scenario | Monthly P&I | Total Interest | Total PMI | Payoff | vs. Base Interest |
|---|---|---|---|---|---|
| ★ Base (6.50%, 30yr) | $2,022.62 | $408,142 | — | Jun 2056 | — |
| Rate +0.5% (7.00%) | $2,128.97 | $446,428 | — | Jun 2056 | +$38,286 |
| Rate −0.5% (6.00%) | $1,918.56 | $370,682 | — | Jun 2056 | -$37,460 |
| 15-Year Term | $2,787.54 | $181,758 | — | Jun 2041 | -$226,385 |
| Extra $500/month | $2,022.62 | $222,590 | — | Jun 2044 | -$185,552 |
💡 What Your Numbers Mean
- Your P&I payment is $2,022.62/month. Total out-of-pocket including taxes, insurance and HOA is $2,522.62/month — 25% more than the base payment.
- Over 360 months, you'll pay $408,142 in interest — 56% of total P&I payments. Switching to a 15-year term would reduce total interest to $181,758 (saving $226,385) but increases the monthly payment.
- Adding $500/month extra to principal would save $185,552 in interest and pay off the loan 12 years 0 months early.
About This Mortgage Calculator
The Mortgage Calculator computes your estimated monthly principal and interest payment for any home loan, and shows you the full amortisation schedule — how every dollar of every payment is split between repaying the loan balance and paying the lender's interest charge. For most people, a mortgage is the largest financial commitment of their lives, which makes understanding the true cost of different loan scenarios essential before signing anything.
The Formula — How It Works
Monthly mortgage payments are calculated using the standard amortising loan formula:
Where: M = monthly payment, P = principal loan amount (home price minus down payment), r = monthly interest rate (annual rate ÷ 12), n = total number of payments (years × 12).
For example, a $320,000 loan at 7% for 30 years: r = 0.07/12 = 0.005833, n = 360, giving M = $320,000 × [0.005833 × (1.005833)³⁶⁰] / [(1.005833)³⁶⁰ − 1] = $2,129/month. Total paid over 30 years: $766,440 — of which $446,440 is interest.
Assumptions and Limitations
- •Only principal and interest are calculated — property taxes, insurance, HOA fees, and PMI are not included
- •This assumes a fixed interest rate for the entire loan term (not applicable to adjustable-rate mortgages)
- •Closing costs (typically 2–5% of the loan amount) are not factored in
- •Extra payments or lump-sum payments that could accelerate payoff are not modelled
- •Results are illustrative estimates — your actual loan offer from a lender may differ
Who Should Use This Calculator
This tool is ideal for first-time home buyers who want to understand how much house they can afford before speaking to a lender. Existing homeowners considering refinancing can quickly compare their current payment to a new rate scenario. Real estate investors can assess whether a property's rental income will cover its financing costs. Anyone comparing different loan structures — 15-year vs. 30-year, different down payment amounts, or different interest rates — can use this tool to instantly quantify the financial trade-offs.
When to Consult a Professional
Before purchasing or refinancing a home, consult a licensed mortgage broker or loan officer for official loan estimates. A HUD-approved housing counsellor (find one at hud.gov) can help first-time buyers understand the full cost of homeownership including taxes, maintenance, and insurance. A financial advisor can help you decide whether buying vs. renting makes sense for your long-term financial picture.
Privacy Notice
All calculations in this mortgage calculator run entirely in your browser. No data you enter — home price, down payment, income, or interest rate — is transmitted to any server or stored anywhere. Your financial information stays completely private on your device. See our Privacy Policy for full details.
When to Use This Calculator
Enter different home prices and down payments to see what monthly payment fits your budget before you start shopping, so you know your real purchasing range.
Compare your current payment to a new rate and term to see how much you would save monthly and over the remaining life of your loan after refinancing.
Run the same loan amount at 15 years vs. 30 years to instantly see the monthly payment difference and total interest saved — a crucial trade-off calculation.
Work backwards from your target monthly payment to find the maximum home price you can afford at current interest rates — before talking to a lender.
Calculate the mortgage payment on a potential investment property to determine whether rental income will cover financing costs and produce positive cash flow.
💡 Pro Tips
A 1% difference in interest rate on a $300,000 mortgage adds up to roughly $60,000 in additional interest over a 30-year loan. Shopping three or more lenders takes a few hours but could save you that amount. Always compare the APR (which includes fees), not just the stated interest rate.
Adding just $100 extra to your monthly mortgage payment on a $300,000 loan at 7% for 30 years cuts 4.5 years off your loan and saves approximately $52,000 in interest. Even small extra principal payments, made consistently, have a dramatic compounding effect on your payoff timeline.
A 20% down payment does more than eliminate PMI — it also means a smaller loan, lower monthly payment, and potentially a better interest rate. If you cannot reach 20% immediately, an 80-10-10 piggyback loan (80% first mortgage, 10% second mortgage, 10% down) can sometimes avoid PMI while requiring less cash upfront.
Get pre-approved by at least three lenders before making an offer on a home. Each lender may offer different rates, points structures, and fee packages. A mortgage broker can shop multiple lenders for you simultaneously, often at no cost to you, since lenders pay their commission.
Frequently Asked Questions
Financial Disclaimer
Mortgage Calculator — Results show principal and interest only and do not include property taxes, homeowner's insurance, PMI, HOA fees, or closing costs. Results are estimates for planning purposes and do not constitute mortgage, financial, or legal advice. Actual loan terms, rates, and payments will be determined by your lender. Always consult a licensed mortgage professional and review your official loan estimate before making any home purchase or refinancing decision.
Related Calculators
Your input is processed locally in your browser and is never stored, transmitted, or shared with any server. See our Privacy Policy.