Loan Comparison Calculator

Compare loan options side by side to see monthly payments, total interest, and overall cost.

How the Loan Comparison Calculator Works

This calculator lets you evaluate up to three loan options side by side. For each loan, you enter the loan amount, annual interest rate, and loan term. The calculator then computes the monthly payment, total interest paid over the life of the loan, and the total cost (principal plus all interest).

The calculations are based on the standard amortization formula for fixed-rate loans. Each payment is applied first to the interest accrued since the last payment, with the remainder reducing the principal balance. Over time, as the principal decreases, a larger portion of each payment goes toward principal.

How to Use the Calculator

Enter the loan amount for each option you want to compare. This is the total amount you plan to borrow.
Input the annual interest rate as a percentage. For example, enter 6.5 for a 6.5% rate.
Set the loan term in years. Common terms are 15, 20, or 30 years for mortgages, and 3 to 7 years for auto or personal loans.
Click "Calculate" to see the comparison results displayed in a clear side-by-side table.

You can leave any loan option blank if you only need to compare two loans. The calculator will only process the fields you fill in.

Understanding Your Results

The results table shows three key metrics for each loan option:

Monthly Payment: The fixed amount you will pay each month for the entire loan term. This includes both principal and interest.
Total Interest: The cumulative interest you will pay over the full loan term. This is the cost of borrowing the money.
Total Cost: The sum of the loan amount and the total interest. This represents the full amount you will have paid by the end of the loan.

Comparing these numbers side by side helps you see the real trade-offs. A lower monthly payment might come with significantly higher total interest if the loan term is longer. A higher interest rate on a shorter term might have a higher monthly payment but lower total cost.

Example Comparison

Suppose you are choosing between two mortgage options for a $300,000 home loan:

Loan A: 6.5% interest, 30-year term
Loan B: 5.8% interest, 15-year term

The calculator will show that Loan A has a lower monthly payment (around $1,896) but much higher total interest (over $382,000). Loan B has a higher monthly payment (around $2,498) but total interest is far lower (around $149,000). The total cost of Loan A is approximately $682,000, while Loan B costs about $449,000.

This example illustrates why comparing both monthly payment and total cost is essential. The "cheaper" monthly payment can cost you significantly more over time.

Common Mistakes When Comparing Loans

Only looking at monthly payments: A lower monthly payment often means a longer term, which increases total interest. Always check total cost.
Ignoring the interest rate difference: Even a small difference in interest rates can have a large impact on total interest, especially on large loan amounts.
Comparing loans with different terms: A 30-year loan and a 15-year loan will have very different monthly payments and total costs. Make sure you are comparing apples to apples, or understand the trade-off.
Forgetting about fees and closing costs: This calculator compares principal and interest only. Actual loan costs may include origination fees, points, or other charges not reflected here.

Limitations of This Calculator

This calculator assumes a fixed interest rate for the entire loan term. It does not account for adjustable-rate mortgages (ARMs), interest-only loans, or loans with balloon payments. It also does not include any fees, points, insurance, or taxes that may be part of a real loan agreement.

The results are estimates for comparison purposes. Always consult with a lender or financial advisor for precise loan terms and costs before making a borrowing decision.

Practical Use Cases

Mortgage shopping: Compare offers from different lenders to find the best combination of rate and term for your budget.
Auto loan decisions: Evaluate whether a shorter loan term with higher payments is worth the interest savings.
Refinancing analysis: Compare your current loan terms against a potential refinance to see if the new loan saves you money over time.
Personal loan evaluation: Compare fixed-rate personal loan offers to choose the most cost-effective option.

Frequently Asked Questions

What is the difference between total interest and total cost?

Total interest is the cumulative interest you pay over the life of the loan. Total cost is the loan amount plus the total interest — it represents everything you will have paid by the end of the loan term.

Why does a longer loan term cost more in total interest?

With a longer term, you make more payments, and the principal is paid down more slowly. This means interest accrues on a larger balance for a longer period, resulting in higher total interest even if the monthly payment is lower.

Can I compare loans with different amounts?

Yes, you can enter different loan amounts for each option. This is useful when comparing loans with different down payments or when evaluating loans for different purchase prices.

Does this calculator include taxes or insurance?

No. This calculator only compares principal and interest. Real estate taxes, homeowners insurance, and mortgage insurance are not included. Those costs would be added to your actual monthly payment but are separate from the loan terms being compared here.

What if I want to compare more than three loans?

This calculator supports up to three loan options at a time. To compare additional loans, you can run the calculator multiple times with different combinations and note the results.