Amortization Calculator 2026

An amortization schedule is a complete table showing every payment over the life of a loan — broken down into principal and interest. In the early months, most of your payment goes to interest. By the end, nearly all of it goes to principal. For a $300,000 mortgage at 6.5% over 30 years, your first payment of $1,896 is split roughly $1,625 interest / $271 principal. By payment 300 (year 25), it flips to $271 interest / $1,625 principal.

The formula is: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P = loan amount, r = monthly interest rate (annual rate ÷ 12), n = total number of payments. Example: $300,000 at 6.5% for 30 years — r = 0.065/12 = 0.005417, n = 360. M = $300,000 × [0.005417 × (1.005417)^360] / [(1.005417)^360 − 1] = $1,896. This payment never changes for a fixed-rate loan.

On a $300,000 mortgage at 6.5%, paying an extra $200/month ($2,096 instead of $1,896) saves approximately $75,000 in interest and cuts the loan term from 30 years to about 24 years — saving 6 years of payments. The earlier you start making extra payments, the more you save, because interest is calculated on the remaining balance.

It shifts dramatically over time. On a $300,000 loan at 6.5% for 30 years: Month 1 — 86% interest, 14% principal. Year 10 — 74% interest, 26% principal. Year 20 — 53% interest, 47% principal. Year 25 — 36% interest, 64% principal. This front-loading of interest is why paying extra in the early years has such a large impact — each dollar of principal reduction eliminates 29 more years of interest on that dollar.

On a $300,000 loan at 6.5%: 30-year — monthly payment $1,896, total interest $382,633, total paid $682,633. 15-year — monthly payment $2,613, total interest $170,367, total paid $470,367. The 15-year saves $212,266 in interest at the cost of $717 more per month. However, the 30-year's lower payment gives you flexibility — you can always pay more when you have it, but aren't forced to.

Yes — the same formula applies. The difference is the term (typically 3–7 years for auto, 2–7 for personal loans) and interest rate (auto: 5–10%, personal: 8–25%). On a $30,000 auto loan at 7% for 60 months: monthly payment = $594, total interest = $5,640. The same loan over 72 months: payment = $512 (saves $82/month) but total interest = $6,872 (pays $1,232 more). Shorter terms always cost less in total interest.

A fully amortized loan means that by making every scheduled payment, the loan balance reaches exactly $0 at the end of the term — no balloon payment required. Most fixed-rate mortgages, auto loans, and personal loans are fully amortizing. In contrast, some loans have a balloon structure where you make smaller payments and then owe a large lump sum at the end. Interest-only loans are also not fully amortizing because the principal never decreases.

Refinancing restarts your amortization clock. If you're 10 years into a 30-year mortgage and refinance into a new 30-year loan, you now have 30 more years of front-loaded interest — even if you got a lower rate. This is why calculating break-even is essential: divide your closing costs by your monthly savings to find how many months until you recoup the costs. Also consider refinancing into a 20-year or 15-year loan to preserve your payoff timeline while capturing the lower rate.