Loan Comparison Calculator
Compare two loans on monthly payment, total interest, and total cost.
Enter principal, rate, and term for each to find the better deal on any loan type.
Loan Comparison helps you evaluate two loan offers side by side to determine which one costs less over the full term.
Monthly Payment Formula:
M = P × [r(1+r)^n] / [(1+r)^n - 1]
Where:
- M = Monthly payment
- P = Principal (loan amount)
- r = Monthly interest rate (annual rate / 12)
- n = Total number of payments (years × 12)
Total Interest:
Total Interest = (M × n) - P
Total Cost:
Total Cost = M × n
What to Compare: When comparing two loans, the lowest monthly payment is not always the best deal. A longer term may have lower monthly payments but cost significantly more in total interest.
Example:
- Loan A: $200,000 at 6.5% for 30 years = $1,264/month, $255,088 total interest
- Loan B: $200,000 at 6.0% for 15 years = $1,688/month, $103,788 total interest
Loan B has higher monthly payments (+$424/month) but saves $151,300 in interest over the life of the loan.
Key Factors:
- Interest rate: Even a 0.25% difference can mean thousands over the loan term.
- Loan term: Shorter terms mean higher payments but much less total interest.
- Loan amount: Sometimes borrowing slightly less makes a significant difference.
- APR vs. rate: the APR (Annual Percentage Rate) folds in origination and closing fees, so it is the honest number to compare when the two offers charge different fees.
Comparing loans of different sizes
Total cost only settles the question when both loans are for the same amount. A smaller loan will almost always show a smaller total, even at a punishing rate, simply because there is less of it. The panel above reports interest per dollar borrowed for exactly this reason: it strips the size out and leaves the price of the money. If Loan A costs $1.28 per dollar borrowed and Loan B costs $2.70, Loan B is the worse deal no matter which line shows the bigger total.
Common Loan Types:
| Type | Typical Term | Rate Range |
|---|---|---|
| 30-year mortgage | 30 years | 5.5–7.5% |
| 15-year mortgage | 15 years | 5.0–7.0% |
| Auto loan | 3–7 years | 4.0–12.0% |
| Personal loan | 2–7 years | 6.0–36.0% |
| Student loan | 10–25 years | 4.0–8.0% |
Tips:
- Always compare total cost, not just monthly payment.
- Factor in your monthly budget: a lower-cost loan is useless if you cannot make the payments.
- Consider refinancing options if rates drop after you take a loan.
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How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.