Loan Comparison Calculator

The loan comparison calculator is built for a common borrowing decision: two lenders quote different rates, terms, fees, or principal amounts, and the cheaper choice is not obvious. Option A might have a higher rate but a shorter term. Option B might advertise a lower payment but run for an extra year. This tool puts both offers through the same fixed-rate amortization formula, then compares monthly payments, total interest, total cost including upfront fees, and the estimated savings from choosing the lower-cost option.

Use it before accepting an auto loan, personal loan, equipment loan, home improvement loan, or any fixed-payment installment offer. If you only need to analyze one loan, use the loan calculator. If the winner must fit monthly income, check the debt-to-income calculator. If the debt is being used to pay off revolving balances, compare the result with the credit-card-payment calculator.

How the calculator treats each offer

Each option has four inputs. Loan amount is the principal being financed. Interest rate is the annual nominal rate entered as a percentage. Term is the repayment period in years. Upfront fees are required costs paid to obtain the loan, such as origination fees, points, application fees, documentation fees, or required closing charges.

The calculation method rounds each term to a whole number of months by multiplying years by 12 and using normal rounding. A 5-year term becomes 60 payments, while a 5.5-year term becomes 66 payments. It then calculates each monthly payment, multiplies by the payment count, subtracts principal to estimate interest, adds upfront fees to get total cost, and declares the lower total-cost option the winner. It separately identifies the option with the lower monthly payment, because that is not always the same option.

Formula used by the calculator

For each option, the payment count is:

$\text{number of payments} = \max\left(1,\operatorname{round}\left(\text{term years} \times 12\right)\right)$

The monthly rate is:

$\text{monthly rate} = \frac{\text{annual rate}}{100 \times 12}$

When the rate is above zero, monthly payment is:

$\text{monthly payment} = \frac{\text{principal} \times \text{monthly rate}}{1 - \left(1 + \text{monthly rate}\right)^{-\text{number of payments}}}$

When the rate is zero, the payment is principal divided by the number of payments. Interest and total cost are:

$\text{interest} = \text{monthly payment} \times \text{number of payments} - \text{principal}$

$\text{total cost} = \text{monthly payment} \times \text{number of payments} + \text{upfront fees}$

The displayed savings are the absolute difference between Option A total cost and Option B total cost.

Worked example

Compare two auto loan offers. Option A finances $30,000 at 7.5% for 5 years with $500 in upfront fees. The term becomes 60 payments. The calculated monthly payment is $601.14. Multiplying by 60 gives $36,068.31 in scheduled payments, so interest is $6,068.31. Adding the $500 fee gives a total cost of $36,568.31.

Option B finances the same $30,000 at 6.9% for 6 years with $900 in upfront fees. The term becomes 72 payments. The monthly payment is lower at $510.03, but scheduled payments total $36,722.22. Interest is $6,722.22, and adding the $900 fee gives a total cost of $37,622.22.

The calculator therefore reports that Option A costs less by $1,053.91, even though Option B has the lower monthly payment. That is the tradeoff the tool is designed to expose: lower payment can be useful for cash flow, but it can also mean more interest over a longer schedule.

How to use the fee fields correctly

Fees can change the answer when rates are close. Put unavoidable borrower-paid costs in the fee field when they are paid up front. If a fee is rolled into the loan balance, include it in the principal instead. If a lender advertises APR, remember that APR may already reflect some prepaid finance charges. Counting the same fee in both the APR and the fee field can make that offer look worse than it is. On the other hand, ignoring a real cash charge can make a teaser rate look better than it is.

For apples-to-apples comparisons, keep the financed amount the same unless the offers truly provide different amounts of money. If Option B finances a warranty or taxes that Option A excludes, the calculator will compare packages, not just credit prices. That can still be useful, but the conclusion should be framed as “this package costs less,” not “this rate is better.”

Caveats and decision guidance

The result assumes fixed rates, full-term repayment, and no late fees, prepayment penalties, taxes, insurance premiums, or optional add-ons. It also does not discount future payments to present value. That is appropriate for a plain consumer comparison, but a business equipment decision may need tax and cash-flow modeling beyond this calculator.

If total cost and monthly payment disagree, decide which constraint is binding. Borrowers with stable income and emergency savings usually benefit from the lower total cost. Borrowers with tight monthly cash flow may need the lower payment, but should recognize the extra interest as the price of flexibility. The personal-loan calculator, apr calculator, and budget calculator can help test whether the preferred offer remains affordable after other bills.

Sources

• CFPB, Auto loans — consumer guidance on shopping for and comparing vehicle financing.
• CFPB, Credit cards — consumer credit education useful for comparing borrowing costs and disclosures.
• Federal Reserve, Consumer Credit - G.19 — official consumer credit data release.
• FTC, ReportFraud.ftc.gov — federal reporting channel for fraud, scams, and deceptive practices.