Loan Comparison Calculator

Compare two loan offers side-by-side. Enter loan amount, APR, and term to see monthly payments and total interest for each option.

Full original guide (expanded)

Loan Comparison Calculator

Evaluate two loan offers side-by-side. Enter loan amount, APR, and term to compare monthly payments, total cost, and interest paid to decide which offer fits your budget.

Loan Option A

Loan Option B

Please enter positive values for loan amounts, APR, and term (in years).

Comparison results

Loan A

Monthly payment

—

Total interest paid

—

Loan B

Monthly payment

—

Total interest paid

—

How the comparison works

Each loan is priced using the standard amortization formula with fixed payments. We use:

\( P = \dfrac{L \cdot r}{1 - (1+r)^{-n}} \)
Where \( L \) is loan amount, \( r \) the monthly interest rate (APR/12), and \( n \) the number of payments.

The calculator then multiplies the payment by the number of payments to get total cost, subtracting the original principal to show total interest paid.

What to compare beyond the payment

  • APR: Reflects both interest rate and fees, making it the best “apples-to-apples” metric.
  • Term length: Longer terms lower the payment but increase total interest. Shorter terms do the opposite.
  • Fees: Origination or underwriting fees can shift the true cost of the loan even if APRs are similar.

Frequently asked questions

Can I add fees to the comparison?

Enter the fee-adjusted loan amount (principal + financed fees) to reflect the true borrowed amount. You can run multiple scenarios quickly and compare.

What if one loan has a lower payment but higher interest?

That usually means the term is longer. Use the total interest output to decide whether the lower monthly payment is worth the extra overall cost.

Can I compare more than two loans?

Run the calculator multiple times and note the results. You can also duplicate the page in your browser to keep multiple comparisons open.

Last accuracy review:

Audit: Needs review
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Note: This page needs review to confirm formulas and sources.
No formulas provided in audit spec.
Variables and units
  • P = principal (loan amount) (currency)
  • r = periodic interest rate (annual rate ÷ payments per year) (1)
  • n = total number of payments (years × payments per year) (count)
  • M = periodic payment for principal + interest (currency)
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verification pending · Last code update: 2026-01-19
Formulas

(Formulas preserved from original page content, if present.)

Version 1.5.0
Citations

Add authoritative sources relevant to this calculator (standards bodies, manuals, official docs).

Changelog
  • 0.1.0-draft — 2026-01-19: Initial draft (review required).