Loan Comparison Calculator

Two lenders offer you $25,000. One quotes 7.5% APR over 5 years; the other quotes 6.4% APR over 6 years. The second has the lower rate and a smaller monthly payment, so it looks like the obvious winner - but it actually costs you more. Over its life the 6-year loan racks up about $5,172 in interest, while the 5-year loan costs only about $5,057 - and the longer term keeps you in debt an extra year, with the gap widening fast as rates and amounts grow. A loan comparison calculator settles this in seconds by putting both loans on the same scale: monthly payment, total interest, and total cost, side by side, with the cheaper option highlighted.

How the comparison is calculated

Each loan's monthly payment uses the standard amortization formula:

where P is the loan amount, r is the monthly rate (APR ÷ 12 ÷ 100), and n is the number of monthly payments (years × 12). From the monthly payment M, the calculator derives the two numbers that decide the winner:

It then ranks every loan by total cost and flags the lowest one as the cheaper option, reporting how much you save against the next-best loan. Using the APR rather than the bare interest rate means fees and points are baked in, so the comparison is fair.

How to use this loan comparison calculator

You only need three numbers per loan, straight off each lender's quote or loan estimate:

1. Loan amount: the principal you would actually finance. If a fee is rolled into the balance, include it here; if it is paid out of pocket, leave it out and note it separately.
2. APR: use the annual percentage rate the lender disclosed, not the "rate from" teaser. The APR includes most fees and is the field that makes loans comparable.
3. Term: the length in years. You can mix terms - that is exactly when this tool earns its keep.
4. Add a third loan if you are weighing three offers, and rename each card to the lender's name so the table reads clearly.
5. Press Compare loans and read the winner at the top, then scan the side-by-side table for the full picture.

The big number at the top is your lifetime savings - the difference in total cost between the cheapest loan and the runner-up.

Who this calculator is for

• Car buyers choosing between a dealer's financing and a credit-union auto loan.
• Borrowers consolidating debt who want to know whether a new personal loan really beats their current balances.
• Anyone with multiple pre-approvals deciding which offer to accept before the rate locks expire.
• People weighing term length - a shorter, higher-payment loan versus a longer, lower-payment one.
• Students and parents comparing private student-loan offers from different lenders.

Worked example 1: same amount, lower rate isn't always cheaper

You need $25,000. Loan A is 7.5% APR / 5 years; Loan B is 6.4% APR / 6 years. Loan A's monthly payment is about $501 and Loan B's is about $419 - so B feels easier. But Loan A's total cost is roughly $30,057 while Loan B's is about $30,172: Loan A is cheaper despite the higher rate and the higher payment, because its shorter term means a full year less of interest. The lesson: the lower rate and the lower payment can both point to the more expensive loan - only total cost tells you which is genuinely cheaper.

Worked example 2: a higher payment that saves thousands

Compare a $30,000 loan at 9% APR over 6 years against the same amount at 7% APR over 4 years. The 6-year loan costs about $541/month; the 4-year loan costs about $718/month. The shorter loan's monthly payment is $177 higher, which can feel painful - but its total cost is about $34,483 versus roughly $38,935 for the longer loan. Choosing the higher monthly payment saves about $4,452 over the life of the loan. This is the most common real-world trade-off the calculator surfaces.

Worked example 3: three offers at once

Borrowing $15,000, you collect three quotes: a bank at 8.5% / 5 yr, a credit union at 7.2% / 5 yr, and a fintech at 6.9% / 7 yr. The credit union wins on total cost (about $17,906), beating the bank (about $18,465) and the fintech (about $18,955) even though the fintech has the lowest rate - its 7-year term piles on extra interest. The calculator names the credit union the cheaper option and shows you save roughly $559 over the runner-up bank.

Reference: how rate and term move total interest

The table below shows the approximate total interest on a $20,000 loan, so you can sanity-check how much each lever matters before you even open the calculator:

Two patterns jump out: total interest roughly doubles from a 3-year to a 7-year term at the same rate, and each 2-point jump in APR adds hundreds to thousands of dollars. That is why a side-by-side comparison beats eyeballing the rate.

Total cost vs. monthly payment: how to decide

Every loan comparison comes down to a tension between two numbers, and the right answer depends on your situation rather than a single rule. Total cost is the disciplined, math-first answer: it is the full price of borrowing, and over many decisions choosing the lowest total cost leaves you with more money. Monthly payment is the cash-flow answer: it is what has to fit inside your budget every month without forcing you to skip other bills or drain savings. The calculator deliberately shows both so you do not have to choose blindly.

A practical way to reconcile them is to start with affordability and then optimize for cost. First, rule out any loan whose monthly payment you cannot comfortably carry - a "cheaper" loan that strains your budget into missed payments and late fees is not actually cheaper. Among the loans that do fit, pick the one with the lowest total cost. In most real comparisons the shorter-term, higher-payment loan wins on total cost, so the only question that matters is whether you can absorb the bigger monthly bite. If you can, the savings shown at the top of the results are essentially free money; if you cannot, a slightly higher total cost is a fair price for breathing room. If cash flow is genuinely tight, mapping out your obligations with a Debt Payoff Calculator first can tell you how much monthly payment you can realistically commit to a new loan.

How loan type changes what you are comparing

The math behind this calculator is identical for any fixed-rate, fully amortizing loan, but the numbers you plug in - and the things to watch for - differ by loan type:

• Auto loans are secured by the vehicle, so APRs are usually lower than unsecured borrowing, and terms commonly run 3 to 7 years. Longer auto terms are tempting because they shrink the payment, but they raise the odds of being "underwater" (owing more than the car is worth). To handle trade-in value and sales tax, price each offer in the Auto Loan Calculator first, then drop the resulting amount, APR and term in here to compare lenders.
• Personal loans are unsecured, so rates are higher and depend heavily on your credit score. Terms are typically 2 to 7 years. Watch for origination fees, which some lenders deduct from the amount you receive - make sure the APR you enter reflects them. The Personal Loan Calculator covers a single offer in more depth.
• Student loans often offer multiple repayment terms and sometimes deferment while in school, which this tool does not model. Compare the standard repayment numbers here, but check each lender's grace-period and deferment rules separately.
• Debt-consolidation loans replace several balances with one. The comparison that matters is the new loan's total cost versus the combined cost of keeping your current debts. Estimate your existing payoff with the Credit Card Payoff Calculator, then test whether a consolidation offer beats it here.

Worked example 4: when the lower payment is the right call

Total cost is not always the deciding factor. Suppose you are comparing a $20,000 loan at 8% APR over 3 years against the same amount at 8% APR over 5 years. The 3-year loan costs about $627/month and roughly $2,562 in total interest; the 5-year loan costs about $406/month and roughly $4,332 in interest. On total cost, the 3-year loan is the clear winner, saving close to $1,768. But if taking the $627 payment would leave you unable to cover an emergency or force you onto a credit card at 24% APR when something breaks, the 5-year loan can be the smarter real-world choice. The $221/month of breathing room may be worth more than the interest you save - especially if there is no prepayment penalty and you can pay extra in good months to close the gap. The calculator gives you the numbers; you supply the judgment about your own cash flow.

What this comparison does not capture

A side-by-side total-cost comparison is the right starting point, but a few real-world factors sit outside the math and deserve a manual check before you sign:

• Prepayment penalties. If a loan charges a fee for paying off early and you expect to pay ahead, its real cost can be higher than the figure shown here. A no-penalty loan at a slightly higher rate can win for early payers.
• Variable rates. The tool treats every APR as fixed for the full term. A variable-rate quote can rise later, so use its current-APR result as a best case and remember it carries rate risk a fixed loan does not.
• Up-front fees paid out of pocket. Fees rolled into the balance are captured if you include them in the loan amount, but origination or application fees paid separately at signing are not. Add them in mentally when two offers are close.
• Optional add-ons. Credit insurance, GAP coverage, or extended warranties bundled into a quote can inflate the financed amount. Strip them out for a clean comparison, then decide on each add-on separately.
• Lender flexibility and service. Hardship deferrals, autopay discounts, the ability to change a due date, and customer-service quality have real value that never shows up in total cost.

Why APR beats the headline interest rate

The most common way borrowers fool themselves is comparing a bare interest rate from one lender against the APR from another. The interest rate only measures the cost of borrowing the principal; the APR rolls in most lender fees and points and expresses the whole thing as a single yearly percentage. Because the federal Truth in Lending Act requires lenders to disclose the APR, it exists precisely so you can put unlike offers on the same footing. A loan advertised at a low rate but loaded with fees can have a markedly higher APR - and a higher true cost - than a plainer loan with a slightly higher rate. Always enter the APR for every loan in this calculator so fees are reflected on both sides. If a lender gives you only a rate plus a fee schedule, convert it to a true APR with the APR Calculator before comparing.

Key terms explained

• Principal: the amount you borrow. Interest is charged on the outstanding principal.
• APR (annual percentage rate): the rate including most fees - the fairest way to compare loans, and a Truth in Lending Act disclosure.
• Term: how long you have to repay. Longer terms lower the monthly payment but raise total interest.
• Monthly payment: the fixed amount you pay each month on a fully amortizing loan.
• Total interest: every dollar of interest paid over the life of the loan.
• Total cost: principal plus total interest - the real price of the loan and the basis for the winner.

Tips for getting an accurate comparison

• Always use APR, not the interest rate, so fees and points are included on both sides.
• Compare on the same amount where possible; if a lender rolls fees into the balance, match it by adding those fees to the other loan's amount.
• Decide what matters more - the lowest monthly payment for cash-flow comfort, or the lowest total cost to save money - and read the table accordingly.
• Check for prepayment penalties. If you plan to pay early, a loan with no penalty and a higher rate can beat a cheaper one that locks you in.
• Get quotes within a short window so the rate-shopping inquiries count as a single event on your credit.

Common pitfalls when comparing loans

The single biggest mistake is anchoring on the monthly payment. Lenders love to advertise a low monthly number because it is easy to afford in the moment, but stretching the term to shrink that number can quietly add thousands in interest. The second trap is comparing a bare interest rate from one lender against an APR from another - never compare unlike numbers. Finally, watch for add-ons such as credit insurance or origination fees that may or may not be in the quoted APR; if in doubt, ask the lender to confirm the loan estimate reflects every fee.

Related concepts and calculators

This page answers "which of these loan offers is cheaper?" Related questions have dedicated tools:

• For a single loan's payment and payoff, use the Loan Calculator.
• To finance a vehicle with trade-in and tax, use the Auto Loan Calculator.
• For unsecured borrowing, use the Personal Loan Calculator.
• To see the month-by-month split of principal and interest, use the Amortization Calculator.
• To convert a rate plus fees into a true APR, use the APR Calculator.
• For interest earned or owed over any period, use the Interest Calculator.
• To roll several balances into one new loan, use the Debt Payoff Calculator or the Credit Card Payoff Calculator.

Sources

• Consumer Financial Protection Bureau (CFPB) - Auto loans: comparing offers and total cost.
• Consumer Financial Protection Bureau (CFPB) - Interest rate vs. APR.
• Consumer Financial Protection Bureau (CFPB) - Truth in Lending Act disclosures and shopping for credit.