Loan Calculator

Compute monthly loan payment and a full amortization schedule. Enter principal, annual interest rate, and term (months or years). Get the payment, the total interest paid, and a period-by-period table showing principal vs interest. Useful for mortgage shopping, refinance comparison, and overpayment modeling.

What the schedule reveals

A 30-year fixed mortgage at 6.5% on $400,000:

• Monthly payment: $2,528
• Total paid over 30 years: $910,178
• Total interest: $510,178

Surprising on a first read. Interest equals 1.27× the principal. The schedule shows that for the first 10 years, ~70% of each payment is interest. By year 20, the balance flips.

Common workflows

Mortgage shopping. Compare 15- vs 30-year, fixed rates from different lenders. Total interest is the headline number.

Refinance decision. Plug current loan, plug refinance terms, compare total remaining interest. Subtract closing costs to find the break-even.

Extra payment impact. Adding $200/month to a 30-year mortgage knocks years off and saves tens of thousands in interest. The schedule shows the new payoff date.

Auto loan. Same math, shorter term. 5-year auto loans amortize fast.

Why a tool

Banks compute these on request, but their numbers come back days later. The tool gives an answer in seconds — useful for negotiation, sanity-checking the lender’s quote, and modeling “what if I pay extra”.

Last updated: 2025-01-15