APR Calculator

APR Calculator reverse-calculates both the note rate and the true Annual Percentage Rate (APR) from a loan's principal, monthly payment, upfront fees, and term. Because APR is based on the net amount financed after fees are deducted, this app shows you exactly how much upfront charges inflate the effective cost above the rate a lender advertises.

WHAT IT CALCULATES
Enter the loan principal, monthly payment, and term, then add any upfront fees — origination fees, points, or dealer charges. The app instantly calculates:
• Note rate — the rate implied by your payment and principal alone
• APR — the true cost rate after fees reduce the amount financed
• APR lift — how many basis points fees add above the note rate
• Finance charge — total interest plus fees over the life of the loan
• Total interest and total paid
• First-month interest and principal breakdown

All results update live as you type, so you can see the fee impact in real time.

SAVE AND COMPARE LENDER OFFERS
Save any set of inputs as a named scenario and build up a list of competing offers. Select up to three scenarios for a side-by-side comparison table showing APR, note rate, finance charge, and total paid — making it easy to spot which deal has the lowest true cost even when the advertised rates look similar.

QUICK-START PRESETS
Not sure where to begin? Built-in presets for personal loans, auto loans, no-fee benchmarks, and high-fee lenders load realistic numbers immediately. Adjust the payment, fees, or term to match your actual quote and the results update instantly.

RECENT SNAPSHOTS
Each time you save a scenario a compact snapshot is recorded so you can review the APR history of your research session without reloading each scenario individually.

REGULATION Z METHODOLOGY
APR is calculated using the U.S. Regulation Z definition for fixed-rate equal-payment loans: the monthly rate is solved by bisection so that the present value of all payments equals the net amount financed. The annual rate is derived by simple monthly-rate multiplication, matching the method required by U.S. federal disclosure rules. Variable-rate and balloon-payment loans are outside scope.

Recent changes:
Performance improvements and bug fixes