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Loan Comparison Calculator

Compare up to 3 loan offers side by side on monthly payment and total interest.

🔒 Runs entirely in your browser — nothing here is ever uploaded

Last reviewed 2026-08-30

About the Loan Comparison Calculator

Compares up to 3 competing loan offers for the same purchase side by side — monthly payment and total interest paid — using the standard fixed-rate amortization formula, and flags when the lowest monthly payment isn't actually the cheapest offer overall.

100% Free Runs in Your Browser No Sign-Up Required
How to use it
  1. Enter the loan amount, APR, and term (in months) for up to 3 offers.
  2. Leave any unused offer's loan amount at 0 to compare just 2 (or 1).
  3. Read each offer's monthly payment and total interest, plus the plain-language comparison insight.
Formula
Monthly payment = P × r × (1+r)^n ÷ [(1+r)^n − 1], where P is the loan amount, r is the monthly interest rate (APR ÷ 12 ÷ 100), and n is the number of monthly payments. Total interest = (monthly payment × n) − P.
Worked example

A $20,000 loan at 6% APR over 36 months costs about $608.42/month with about $1,903.12 total interest; the same $20,000 at 5% APR over 60 months costs less per month (about $377.36) but more in total interest (about $2,641.60).

Interpreting your result

Assumes a fixed-rate, fully-amortizing loan for every offer — no balloon payment, no variable-rate adjustment, and no origination fees or points factored in. If any offer carries fees the others don't, factor those in separately.

Recommendations
  • A lower monthly payment often comes from a longer term, not a better rate — always check total interest alongside the monthly payment.
  • Two offers with the same total interest can still differ a lot in monthly payment if their terms differ.
  • This tool doesn't include fees — ask each lender for the full cost breakdown.
Frequently asked questions
Because it can still be cheaper overall — a shorter term or lower rate often means less total interest paid over the life of the loan.
See the full methodology and sources for every finance calculator
Disclaimer

Illustrative estimate only, not financial or tax advice. Verify figures with a licensed adviser or your local tax authority.