Credit-card rate calculator
Infer nominal and effective annual rates from balance, fixed monthly payment and term under an equal-installment model.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Credit-card JSON
Rate result
Nominal APR, monthly rate and effective APR are shown.
Enter credit-card JSON to calculate
: 0 · : 0 · : 0
What this tool does
- Estimate the implied rate of a card installment plan.
- Compare nominal APR with monthly-compounded effective APR.
Example
Input
{"principal":10000,"payment":879.16,"months":12}Output
Monthly rate / 月利率: 0.83% Nominal annual rate / 名义年利率: 10.00% Effective annual rate / 实际年化利率: 10.47%
Balance and payment are currency amounts and term is months; nominal APR is monthly rate times 12, while effective APR compounds monthly.
Frequently asked questions
What if payment is below principal divided by term?
That is impossible under a non-negative equal-installment rate, so an explicit error is returned.
How is effective APR computed?
The monthly rate is compounded for 12 months: (1+r_month)^12-1.
Are fees included?
There is no fee field; include a fee in balance or payment before calculating.
Keywords：信用卡利率年化利率月利率APRcredit cardrate