Loan Comparison Calculator

How to Use This Tool

Enter the full details for two loan options you are considering in the input sections. For each loan, provide the total loan amount, annual interest rate, loan term in years, repayment frequency, and compounding frequency. Click the Calculate Comparison button to see a side-by-side breakdown of costs and payments. Use the Reset All button to clear all inputs and start over. You can copy the full results to your clipboard using the copy button in the results section.

Formula and Logic

This calculator uses standard amortization formulas to compute loan repayment details:

• Periodic interest rate is derived from the annual rate and compounding frequency: (Annual Rate / 100) / Compounding Frequency per year.
• Effective annual rate accounts for compounding: (1 + Periodic Rate) ^ Compounding Frequency - 1.
• Repayment period rate converts the effective annual rate to the frequency of your repayments: (1 + Effective Annual Rate) ^ (1 / Repayments per Year) - 1.
• Periodic repayment amount is calculated using the standard amortization formula: Loan Amount * (Repayment Period Rate * (1 + Repayment Period Rate) ^ Total Repayments) / ((1 + Repayment Period Rate) ^ Total Repayments - 1).
• Total repaid is periodic payment multiplied by total number of repayments (Term * Repayments per Year).
• Total interest paid is total repaid minus the original loan amount.

All currency values are formatted in USD, but the math applies to any currency.

Practical Notes

When comparing loans, keep these finance-specific factors in mind:

• Lower interest rates do not always mean lower total costs if the loan term is longer, as you will pay interest for more periods.
• Compounding frequency matters: more frequent compounding (e.g., monthly vs. annually) increases the effective interest rate you pay.
• Repayment frequency changes your cash flow: biweekly or weekly repayments reduce total interest paid over time by shortening the effective loan term.
• Consider all fees: this calculator only accounts for interest, not origination fees, closing costs, or prepayment penalties that may apply to your loan.
• Tax deductions for mortgage interest may reduce your effective cost if you qualify, but this calculator does not account for tax implications.

Why This Tool Is Useful

Loan offers often highlight monthly payments or interest rates in isolation, making it hard to see the full picture. This tool lets you compare all key cost factors side by side, including total interest paid and overall loan cost. It helps you avoid choosing a loan with a lower monthly payment that costs thousands more in interest over the term. Financial planners, homebuyers, and anyone taking on debt can use this to make data-driven borrowing decisions that fit their budget.

Frequently Asked Questions

What if my loan has an introductory teaser rate?

This calculator assumes a fixed interest rate for the full loan term. For loans with variable or teaser rates, calculate the cost for the introductory period separately, then run a second calculation for the remaining term with the adjusted rate to estimate total costs.

Does repayment frequency affect my credit score?

Repayment frequency does not directly impact your credit score as long as you make all payments on time. More frequent repayments can help you pay off the loan faster, which may improve your credit utilization ratio over time.

Can I compare loans with different amounts or terms?

Yes, this tool allows you to enter completely different loan amounts, terms, and rates for each option. This is useful for comparing a shorter-term loan with a higher monthly payment against a longer-term loan with lower payments, for example.

Additional Guidance

Always request a full loan estimate from your lender that includes all fees and charges before making a final decision. Use this calculator to narrow down your options, then verify the numbers with your lender’s official disclosures. If you are comparing mortgage loans, factor in property taxes, insurance, and PMI if applicable, as these are often added to your monthly payment but not included in the base loan interest calculation. For auto or personal loans, check if there are prepayment penalties that would apply if you pay off the loan early, as this can change the total cost of the loan.