How is a monthly mortgage payment calculated?

Using the formula M = P[r(1+r)^n]/[(1+r)^n-1], where P is the loan principal, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of monthly payments.

What is a good mortgage interest rate in 2025?

In the US, 30-year fixed rates average around 6.7% and 15-year rates around 6.2% in 2025. UK rates are around 4.8%, German rates around 3.7%, and Indian home loan rates average 8.5–9%.

How much does a 1% rate difference cost over 30 years?

On a $400,000 loan, a 1% higher rate adds approximately $80,000–$90,000 in total interest over a 30-year term — roughly $230 more per month.

Mortgage Repayment Calculator — Monthly Payment & Amortization 2025

Use this free mortgage repayment calculator to find your exact monthly payment, total interest paid, and the full amortization breakdown over your loan term. Whether you're comparing a 15-year vs 30-year mortgage, evaluating variable vs fixed rates, or shopping across markets — our tool applies the standard annuity formula used by banks and mortgage brokers worldwide. Instantly see how much of each payment goes to principal versus interest, and how your equity builds over time. Supports rate presets for the US, UK, Germany, India, Singapore, and Japan.

Loan Details

Region / Country

Home Loan Amount USD

Down Payment

$ 20%

Loan amount = Home price − Down payment

Annual Interest Rate 2025 Rate

Loan Term 30 years

5 yr101520253040 yr

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Monthly Payment —

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Enter your loan details and click Calculate to see your amortization schedule and breakdown.

How Mortgage Repayment Is Calculated

The monthly mortgage payment (M) is calculated using the standard annuity formula:

M = P × [ r(1+r)ⁿ ] / [ (1+r)ⁿ − 1 ]

Where: P = loan principal, r = monthly interest rate (annual rate ÷ 12 ÷ 100), n = total monthly payments (years × 12). Each payment covers interest accrued that month plus a portion of principal. As the balance decreases, the interest portion shrinks and the principal portion grows — this is the amortization process.

Frequently Asked Questions

Your monthly payment is calculated using the annuity formula: M = P[r(1+r)^n]/[(1+r)^n-1]. P is the loan principal, r is the monthly rate (annual rate ÷ 12), and n is the number of payments. Early payments are mostly interest; later payments are mostly principal.

As of 2025, the US 30-year fixed mortgage rate averages approximately 6.7% and the 15-year fixed rate averages 6.2%, according to Freddie Mac's Primary Mortgage Market Survey. Rates fluctuate weekly based on Treasury bond yields and Fed policy.

A 15-year mortgage has higher monthly payments but saves significantly on total interest (often 50–60% less). A 30-year mortgage offers lower payments and more cash flow flexibility. If you can comfortably afford the 15-year payment, you'll pay off the home faster and save tens of thousands in interest.

Mortgage Repayment Calculator

How Mortgage Repayment Is Calculated

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