How to use this calculator
- Enter or choose work out.
- Enter or choose loan balance.
- Enter or choose interest rate (per year).
- The monthly repayment updates as you type. Use Copy result or Share to keep it.
Method
Payment = P × r ÷ (1 − (1 + r)^−n); Time for a fixed payment: n = −ln(1 − P × r ÷ Payment) ÷ ln(1 + r), rounded up (the last payment is smaller)
- P
- loan balance
- r
- annual rate ÷ 12
- n
- number of monthly payments
Worked example
- r = 6% ÷ 12 = 0.005; n = 240.
- Payment = 100,000 × 0.005 ÷ (1 − 1.005^−240) = 716.43.
- Total repaid = 716.4311 × 240 = 171,943.45, so interest is 71,943.45.
A 100,000 loan at 6% over 20 years costs 716.43 a month and 71,943.45 in interest.
What the result means
Switch to “Time to repay” and enter a slightly higher payment to see how much sooner the loan is cleared: on long loans, a small increase removes years of interest.
Assumptions and limits
- Fixed interest rate, charged monthly at the annual rate ÷ 12.
- Payments are made at the end of each month with no fees.
- Variable-rate loans, payment holidays and lender fees are not modelled.
- Some lenders calculate interest daily, which changes the figures slightly.
Questions
How is this different from the EMI calculator?
The EMI calculator gives the payment for a term. This one also works backwards from a payment you choose to the time it takes, and shows the schedule year by year.
Why is the last payment smaller?
With a fixed payment the balance rarely divides exactly, so the final payment is just what is left.
Please note: This calculator gives estimates for planning. It is not financial advice, and lenders’ actual terms, fees and rounding may differ.