Money

Amortization Schedule Calculator

Every payment on a loan, month by month — what goes to interest, what goes to principal, and when that balance finally tips.

Enter the loan amount, rate and term to see the full schedule.

Loan amount

Interest rate

Loan term

First payment month

Optional. Adds real dates and a payoff month to the schedule.

Extra each month

Optional. Goes straight to principal and shortens the loan.

Exact calculation. Given your inputs, this is the answer — no estimation involved.

How this calculator works

A fixed-rate loan has a level payment, but what that payment buys changes every month. Interest is charged on whatever you still owe, so early on almost all of it is interest and barely any touches the balance. As the balance falls the interest falls with it, and more of the same payment goes to principal.

The schedule is generated payment by payment rather than approximated, and the final payment is trimmed to land the balance exactly on zero — the same thing a servicer does. Without that trim the total interest is overstated by up to one payment.

The number most people find surprising is the crossover: the month principal first exceeds interest. On a $200,000 mortgage at 6% over 30 years it does not happen until month 223 — year eighteen and a half. For the first three fifths of the loan, more than half of every payment is rent on the money.

Enter a first payment month and every row gets a real date, so you can see the actual payoff month rather than counting periods.

The formula

Exactly what happens to your numbers, step by step.

The payment
```
payment = P · i ÷ (1 − (1 + i)⁻ⁿ)
```
P the principal, i the monthly rate (annual ÷ 12), n the number of payments.

Each month

interest  = balance × i
principal = payment − interest
balance   = balance − principal

The crossover
```
the first month where principal > interest
```
Later than almost anyone expects, and later still on longer terms.

A worked example

A $200,000 mortgage at 6% over 30 years, first payment October 2026.

What you enter

Loan amount: $200,000
Interest rate: 6%
Term: 30 years
First payment: 2026-10

The working

Monthly payment: $1,199.10
First payment splits: $1,000.00 interest · $199.10 principal
After ten years you have repaid: $32,628.55 of $200,000
Principal overtakes interest in: month 223 — April 2045
Final payment: September 2056
Total interest: $231,676.38

$1,199.10 a month · $231,676 of interest · paid off September 2056

Two things worth sitting with. The interest over the full term is more than the house price — $431,676 paid for $200,000 borrowed. And after ten full years, a third of the term, only 16% of the balance is gone. That is not a bad loan; that is how amortisation works, and it is the argument for the extra-payment field.

Assumptions

Every result here rests on these. Change your inputs and the result changes with them.

A fixed interest rate for the whole term.
Payments made monthly, on schedule, in equal amounts.
Interest accrues monthly on the outstanding balance at the annual rate divided by twelve.
Extra payments are applied to principal immediately and every month.
No fees, insurance, escrow or prepayment penalties.

What this cannot tell you

Rows are labelled by month, not by a specific day. Your due date is set by the loan agreement, and many lenders accrue interest daily rather than monthly — so a servicer statement can differ by a few dollars in any given month.
This is principal and interest only. A mortgage payment usually also includes property tax, insurance, HOA and PMI; the Mortgage Payment Calculator covers the whole figure.
Adjustable-rate loans are not modelled. A schedule for an ARM is only valid until the first reset.
It assumes extra payments are applied to principal. Some servicers apply them to the next instalment instead unless you say otherwise, which changes nothing about what you owe — check how yours handles it.
Biweekly payment plans are not modelled here; the Mortgage Payoff Calculator handles those.

Questions people ask

What is an amortization schedule?

A table of every payment on a loan, showing how each one splits between interest and principal, and what is left owing afterwards. It is how you check a lender’s figures, and how you see what a loan actually costs rather than just what it costs per month.

Why is so much of my early payment interest?

Because interest is charged on what you still owe, and at the start you owe almost all of it. On a $200,000 loan at 6%, the first month’s interest is $1,000 — of an $1,199 payment. Only $199 comes off the balance. As the balance falls the interest falls with it, and the split shifts.

When does more of the payment go to principal than interest?

Later than most people expect. On a 30-year loan at 6% it is month 223 — over eighteen years in. Higher rates push it later, shorter terms pull it much earlier: the same loan over 15 years crosses over in the first year.

How much do extra payments actually save?

More than seems reasonable, because every extra dollar goes straight to principal and stops accruing interest for the rest of the term. Enter an amount above and the schedule shows the new payoff date and the interest saved side by side.

Does this match my lender’s statement?

It should be very close on a monthly-accrual loan. Differences of a few dollars usually mean your lender accrues interest daily, or your payment date falls at a different point in the month. If it is off by a lot, check whether your payment includes escrow for tax and insurance — this calculator is principal and interest only.

Sources and review

This calculator uses standard arithmetic with no external rules or published rates, so there is nothing to cite beyond the formulas shown above.

Methodology version 1.0.0 · Last reviewed September 6, 2026