How it works
Calculate equal monthly principal-and-interest payments for a fixed-rate loan. Fees and insurance are excluded.
PMT = Pr/[1−(1+r)⁻ⁿ], r = annual/12
Worked example
Show example inputs and result
Loan principal: 20,000 · Annual interest rate: 10 · Monthly payments: 36.
- Monthly payment
- 645.34374388
- Total interest
- 3,232.37477956
- Total paid
- 23,232.37477956
Questions and answers
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy