Loan Payment Calculator
What is my monthly payment and total interest on a fixed-rate loan?
Single calculationv1.0.0Verified 2026-11-01Runs in your browser
Spec sheet
amortizing_fixed_rate · v1.0.0Method
Standard amortization (annuity) formula
- 01
r = annual rate ÷ 12 - 02
payment = P · r / (1 − (1 + r)^−n) - 03
If r = 0: payment = P ÷ n
Limits — read before relying on it
- Fixed rate with equal monthly payments; adjustable-rate loans are not modeled.
- Taxes, insurance (escrow) and PMI are excluded.
- Interest is computed monthly on the outstanding balance; daily-interest loans can differ by a few cents.
Sources
- Annuity payment formula (present value of an ordinary annuity)formula