Loan Comparison Calculator
Compare 2 or 3 loans side-by-side — monthly payment, total interest, and total cost. Cheapest highlighted.
Written by Golam Rabbani, Founder & Lead Engineer
How to use this loan comparison calculator
- Choose a currency at the top so the numbers display consistently.
- Enter the principal, APR, and term in years for Loan A and Loan B.
- Optionally click "Add a third loan" to compare a third offer (Loan C).
- Press Compare to see each loan's monthly payment, total interest, and total cost side-by-side.
- The cheapest by total cost is highlighted in green. Use Copy to save the comparison.
About this loan comparison calculator
A loan comparison calculator runs the same amortization math on every loan offer at the same time, so you can see them side-by-side. For each loan it computes the monthly payment using the standard fixed-rate amortization formula M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the principal, r is the monthly interest rate (APR ÷ 12), and n is the term in months. Total cost is M × n; total interest is total cost minus principal. The "cheapest" row in the result is the one with the lowest total cost across the term, not just the lowest monthly payment.
For example, comparing a 5-year $25,000 loan at 6.5% versus a 7-year $25,000 loan at 6.0%: the 5-year option has a higher monthly payment (~$489.06) but lower total interest (~$4,343), while the 7-year option has a lower monthly payment (~$365.39) but higher total interest (~$5,693). This trade-off — lower monthly vs. lower total — is the central lesson. The U.S. Consumer Financial Protection Bureau publishes the same comparison guidance at consumerfinance.gov/owning-a-home/loan-options.
This tool is for estimation only and is not financial advice — always confirm the actual offer terms with each lender in writing, and consult a qualified financial advisor before signing.
FAQ
- How is "cheapest" decided?
- The tool highlights the loan with the lowest total cost (monthly payment × number of payments). That is the right comparison when the loans are funding the same purchase — you pay back less in total over the term.
- Why is a lower APR not always cheapest?
- Because term matters. A lower APR over a much longer term can total more interest than a higher APR over a shorter term. The total-cost column makes this explicit.
- Should I always pick the lowest total cost?
- Not necessarily. A loan with the lowest total cost may have a monthly payment you cannot comfortably afford. Use this tool to find the lowest-cost option that fits your monthly budget.
- Does this work for fixed-rate loans only?
- Yes — the math assumes a fixed APR for the entire term. Variable-rate loans cannot be compared exactly because the future rate is unknown; you can still use this tool by entering the current rate and re-running with worst-case rate estimates.
- Do extra fees or points show up here?
- No — this is a pure APR-and-term comparison. To compare lenders that quote fees or points, fold those into the principal before entering it, or compare the lender-disclosed APR figures (which already include most fees in the U.S.).
- Is my data sent anywhere?
- No. The comparison runs entirely in your browser. Numbers are never uploaded, logged, or stored.