APR vs. interest rate

Interest is one part of cost

An interest rate describes the charge for borrowing the principal. APR is a broader annualized cost measure that includes interest and certain finance charges. It is important to compare APR with APR rather than assume it means the same thing as the nominal interest rate.

Why the calculator asks for an interest rate

The calculator uses a nominal annual interest rate divided by 12 to model equal monthly periods. It assumes no fees. If you enter a disclosed APR that incorporates fees, the resulting payment may not match the actual payment. Use the contract rate for this simplified model and rely on the lender’s disclosure for the real APR and repayment obligation.

A fee can change how you see the offer

Imagine a hypothetical agreement with a face amount of $1,000, but only $950 delivered after a deduction. The useful cash and the stated principal are now different amounts. This example does not calculate an APR or describe a real product; it shows why recording the net cash received matters in a comparison.

Use a side-by-side worksheet

Write down the principal, actual cash received, nominal rate, disclosed APR, number of payments, payment size, upfront costs and total scheduled repayment for each offer. A blank field is a question to resolve, not a reason to substitute a guess.

Compare the complete agreement

Even when two offers show the same APR, terms, payment timing or other conditions can differ. Review the complete documents, including late-payment and early-repayment terms. A calculator is a way to explore a model, not a source of current legal disclosures.