InstalmentLoans

Loan Amortisation Calculator

A loan amortisation calculator builds a schedule that splits every repayment into interest and capital. It also reports the fixed monthly repayment and the total cost of credit over the life of the loan.

By the InstalmentLoans Editorial Team · Last updated 2 October 2026

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How this calculator works

An amortisation schedule splits every repayment into interest and capital. Early repayments are mostly interest; later repayments are mostly capital.

For each month:

  1. Interest = current balance * r, where r = annual rate / 12 / 100.
  2. Capital = monthly repayment - interest.
  3. New balance = current balance - capital.

The fixed monthly repayment comes from M = P * r * (1 + r)^n / ((1 + r)^n - 1). The final repayment is adjusted so the balance lands exactly on zero.

With a 0% rate, every repayment is pure capital and the balance falls in equal steps. Yearly totals are shown to keep the table readable.

Frequently asked questions

What is an amortisation schedule?
It is a table of every repayment showing how much goes to interest, how much goes to capital and the balance left after each payment.
Why is most of my early repayment interest?
Interest is charged on the outstanding balance. At the start the balance is largest, so the interest portion is largest. As the balance falls, more of each repayment goes to capital.
What happens on the final repayment?
The last repayment is adjusted so the remaining balance reaches exactly zero. It may be slightly smaller than the regular repayment because of rounding in earlier months.
Does a 0% loan still amortise?
Yes. With no interest, the repayment is the capital divided by the number of months, and every repayment reduces the balance by the same amount.

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