Payment arithmetic starts with an interest rate
Our standard repayment model uses a borrowed amount, a nominal annual interest rate and a term in months. It estimates equal monthly principal-and-interest payments. It does not automatically identify which lender fees should be included in an annual percentage rate disclosure.
APR can reflect costs beyond the stated interest rate. Which charges are included and how a lender must disclose them depend on the applicable rules and product. Do not take a fee-free mathematical rate and describe it as a legally compliant APR without those inputs and rules.
A useful way to compare offers
Write down the interest rate, fees paid upfront, fees added to the balance, payment schedule, term and any early-repayment terms for each offer. If a fee is financed, it can increase the amount borrowed. If a fee is paid in cash, it affects your total outlay even when the monthly payment stays the same.
Use the loan calculator for the repayment schedule. Then keep a separate line for costs excluded from that schedule. This makes it easier to see why the lowest advertised rate does not necessarily produce the lowest overall cost.
Avoid comparing different products as if they were identical
A variable rate can change after the initial period. A balloon payment leaves a larger final payment. An interest-only period delays principal repayment. Those structures are outside this calculator's standard equal-payment model.
The CFPB source below explains the distinction for US mortgages. It should not be treated as the disclosure rule for every country or every form of credit. Use the lender's official documents and the relevant local regulator when checking a real agreement.