Loan Amortisation Calculator

Created by Arunangshu DasReviewed Nov 14, 2026

Build the full repayment schedule of a loan: each payment's interest, principal and remaining balance.

Enter the amount borrowed, the annual rate and the term in months. Fees, taxes and extra payments are not included.

Payment, total interest and where the schedule turns

Enter the loan terms or load the worked example.

The annual rate is a nominal rate charged at one twelfth each month on the balance still owed, with payments at the end of each month. Interest is rounded to 0.01 each month and the last payment clears what remains. A lender's own rounding, day count, fees, first-payment date and any rate change or extra payment give a different schedule.

Learn how to read the schedule

Follow one loan row by row and see why early payments are mostly interest.

Read the loan amortisation guide

Formula and methodology

Interest = balance × r, with r = annual rate ÷ 12 ÷ 100; principal = payment − interest; new balance = balance − principal.

The monthly payment is the level payment of the Loan EMI model: the smallest payment in steps of 0.01 whose ledger clears the loan within the term. Each month, interest = balance × annual rate ÷ 12, rounded to 0.01; principal = payment − interest; new balance = balance − principal. The last payment is the remaining balance plus its interest. Loan years group the payments in twelves from the first payment, and each yearly total is the sum of its rows. Two points are read from the rows: the first payment whose principal part is larger than its interest part, and the first payment after which half or less of the loan is still owed.

Definitions

Amortisation is the repayment of a loan by regular payments that each cover the interest for the period and repay part of the amount borrowed. An amortisation schedule lists every payment with its interest part, its principal part and the balance still owed after it. With a level payment the interest part falls and the principal part rises from one payment to the next, because interest is charged on a shrinking balance.

Verified worked examples

Borrow 300,000 at 6% a year over 360 months. The payment is 1,798.66. The first payment holds 1,500.00 of interest and 298.66 of principal, leaving 299,701.34. In loan year 1 the payments total 21,583.92, of which 17,899.80 is interest and 3,684.12 is principal, leaving 296,315.88. Payment 222 still holds 899.42 of interest and 899.24 of principal; payment 223 is the first with more principal, 903.74 against 894.92. More than half of the loan is owed until payment 252, after which 149,811.62 remains. The final payment is 1,790.23. Total interest is 347,509.17 and all payments total 647,509.17.

Interpretation

Read across a row to see where one payment goes, and down the balance column to see what you would still owe at any point. The early rows are mostly interest, so the balance falls slowly at first and quickly at the end. The payment at which principal overtakes interest and the payment at which half the loan is repaid are usually well past the middle of a long loan at a high rate, and near the start of a short one. The yearly totals show how much of a year's payments was interest.

Inputs and interpretation

Enter the amount borrowed, the annual rate and the term in complete months, then build the schedule. Totals are listed for every loan year. Choose a loan year to list its payments, or choose all payments for the full schedule. Choose a market for number formatting only.

Assumptions and limitations

One amount borrowed at the start, a fixed nominal annual rate charged at one twelfth each month on the balance still owed, equal model months, interest rounded half up to 0.01 each month, and level payments at the end of each month. Loan years count twelve payments from the first payment and are not calendar or tax years. There are no fees, taxes, insurance, extra payments, missed payments or rate changes.

Supported domain and common mistakes

Amounts above 0 up to 1 trillion with at most 2 decimal places; annual rates from 0% to 100%; terms from 1 to 600 whole months. The schedule does not model extra or missed payments, a rate that changes, interest-only or deferred periods, a balloon, payments other than monthly, daily interest between actual dates, or a lender's own rounding. It does not show negative amortisation, because the payment always covers the month's interest.

Do not expect half the loan to be repaid at half the term: in the example 213,144.12 of 300,000 is still owed after 180 of 360 payments. Do not read loan years as tax years when totalling interest for a return. Do not expect a lender's schedule to match to the cent; day counts and rounding differ. Do not treat the first payment with more principal than interest as a target; it only describes the schedule.

Frequently asked questions

What is a loan amortisation schedule?

A table with one row for each payment, showing the amount paid, the interest part, the principal part and the balance still owed afterwards. For 300,000 at 6% over 360 months the first row is 1,798.66 paid, 1,500.00 interest, 298.66 principal and 299,701.34 owed.

How are the interest and principal in each payment worked out?

Interest for the month is the balance owed × the annual rate ÷ 12, rounded to 0.01. The rest of the payment is principal and reduces the balance. On 299,701.34 at 6% the second month's interest is 1,498.51, so 300.15 of the 1,798.66 is principal.

Why is so much of an early payment interest?

Interest is charged on the whole balance, and at the start nearly all of the loan is still owed. In the example, 17,899.80 of the first year's 21,583.92 is interest. As the balance falls, the interest part shrinks and the principal part grows.

When does a payment hold more principal than interest?

It depends on the rate and the term. For 300,000 at 6% over 360 months it is payment 223. At 4% it is payment 153 and at 7% payment 242. Over 180 months at 6% it is payment 43. The calculator reads it from the schedule's own rows.

How much do I still owe after a given number of payments?

Read the balance in that payment's row. In the example the balance is 279,162.50 after 60 payments, 251,055.83 after 120 and 213,144.12 after 180. A lender's settlement figure can differ because of fees, interest to the settlement date and rounding.

Why is the final payment different from the others?

The payment is rounded up to the next 0.01, so each payment repays a tiny amount more than the exact figure. The last payment is whatever balance and interest remain: 1,790.23 instead of 1,798.66 in the example.

Sources and educational scope

Educational arithmetic for a fixed-rate loan repaid by level monthly payments. It is not a loan offer, a lender's repayment schedule, a statement for tax purposes or financial advice. A lender's own rounding, day count, fees, payment dates and conventions will differ; rely on the lender's documents.

Reviewed 2026-11-14. AI-assisted content under operator editorial responsibility. No independent expert financial review is claimed.