Mortgage Payment Breakdown Calculator

See how your mortgage payment splits between principal and interest over time.

By Konstantin Iakovlev · Updated September 2026 · Source: CFPB — Owning a Home

$
%

Monthly Payment

$2,212.24

Total Interest

$446,405.71

Payment Breakdown

First Payment - Principal$316.40
First Payment - Interest$1,895.83
Last Payment - Principal$2,200.32
Last Payment - Interest$11.92
Total Interest Paid$446,405.71
Total Cost$796,405.71

Use the Mortgage Payment Breakdown Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Every mortgage payment splits into two parts, principal and interest, and the proportion shifts steadily as the loan ages. Seeing that split laid out matters for planning: at a 6.5% rate on a 30-year fixed loan, about 86% of the first payment is interest, and principal does not overtake interest until the 20th year.

The breakdown rests on the standard amortization formula, P = L[c(1 + c)^n]/[(1 + c)^n – 1], in which P is the monthly payment, L is the loan amount, c is the monthly interest rate (annual rate / 12), and n is the number of months. Each month's interest is the outstanding balance times the monthly rate, and whatever is left of the payment goes to principal. The calculator shows that split for the first and the last payment, along with total interest (the payment times the number of months, minus the loan amount) and total cost.

Most people are startled by the total interest a loan accrues across its full life, and laying it out plainly is half the point of this view. Extra payments are not modeled here, but they are the main lever: paying even a little above the required amount each month shrinks both the time to payoff and the lifetime interest, and it's one of the fastest ways to build equity.

Example: $350,000 Mortgage Payment Breakdown

  1. 1 Input a loan amount of $350,000, an annual interest rate of 6.5%, and a loan term of 30 years (360 months).
  2. 2 Monthly payment: c = 0.065 / 12 = 0.0054167, so P = $350,000 × [c(1 + c)^360] / [(1 + c)^360 – 1] = $2,212.24.
  3. 3 First payment: interest is $350,000 × 0.065 / 12 = $1,895.83 and the remaining $316.40 goes to principal. Last payment: $11.92 interest and $2,200.32 principal. Total interest comes to $446,405.71, so the loan costs $796,405.71 in all.
  4. 4 Walking the same loan month by month (outside this calculator), payment 180 is still $1,380.11 interest and $832.13 principal, and principal first exceeds interest at payment 233, in the 20th year. Because early payments are mostly interest, extra principal paid early in the loan saves the most.

Source: CFPB — Owning a Home · Last updated: September 2026

Frequently Asked Questions

How much of my mortgage payment goes to interest vs principal?
In the early years, most of the payment goes to interest. On a $300,000 30-year mortgage at 6.5%, about 86% of the first $1,896 payment is interest ($1,625) and 14% is principal ($271). Even in year 15 about 62% of each payment is still interest; the split reaches 50/50 only in the 20th year.
When does my mortgage payment start paying more principal than interest?
For a 30-year mortgage, the crossover point typically occurs around year 17-20 depending on the interest rate. Higher rates push the crossover later. For a 15-year mortgage, the crossover happens much sooner, around year 5-7.
Does making extra principal payments save a lot on interest?
Yes. Adding $200 extra monthly to a $300,000 30-year mortgage at 6.5% saves over $100,000 in interest and pays off the loan about 7 years early. Even one extra payment per year shaves about five and a half years off the loan term at that rate.

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