Result
Annual rate
—
Your inputs are stored in this browser, so everything is still here next time. Nothing is sent to a server.
This calculation is for informational purposes only and does not replace advice from a qualified professional. Formulas and rates may not fit your exact situation — double-check the figures before making decisions.
How it is calculated
There's no direct formula for the rate given a known payment — the annuity equation has to be solved for the rate numerically. The calculator searches by bisection: at each trial rate it computes the annuity payment and compares it to the one entered, narrowing the range until it finds a rate accurate to within a hundredth of a percent.
If the entered payment is less than or equal to the loan amount divided by the term (i.e. smaller than the payment at a zero rate), no solution exists — such a payment wouldn't even cover the principal with no interest, and the calculator shows a dash.
The result assumes a pure annuity schedule with no early repayments or extra fees. If the loan carries fees or uneven payments, the real rate may differ from the one computed here.