Extra Payment Loan Calculator

What each input means

• Loan balance, annual rate (%), remaining term (years) — Used to compute the baseline amortizing payment.
• Extra payment per month — Added to that payment; payoff is simulated month-by-month until the balance is paid.

Formula used

Baseline payment uses fixed-rate amortization M = P × r ÷ (1 − (1 + r)⁻ⁿ) with r monthly and n months. Interest totals sum each month’s balance × r until payoff for the baseline schedule vs the increased-payment schedule.

Assumes the extra pays down principal immediately; ignores fees, taxes, and escrow.