Mortgage Amortization Calculator

Each month: interest = balance × monthly rate; principal = payment − interest (+ any prepayment); balance −= principal. Equity = home value − balance, with the value optionally appreciating. PMI ends when balance ≤ 80% of value.

The schedule is the point

Most mortgage tools give you a monthly payment and stop. This one gives you the whole story: a row for every payment, split into the interest charged on the outstanding balance and the principal that actually reduces the debt, with the balance falling and your equity rising alongside. The table shows year-end rows by default to stay readable — expand it to every month, or download the full schedule as CSV for your records, tax workings or a lender.

Because interest is charged on the balance, which is largest at the start, the early payments are mostly interest and barely dent the principal. As the balance falls the split steadily reverses, so the back half of a long loan pays down far faster than the front half. The chart shows this as the cumulative principal overtaking the shrinking balance, with the equity line climbing throughout.

Worked example — $400,000 home, 20% down ($320,000 loan) at 6.5% over 30 years ($2,023 a month): Month 1: about $1,733 interest, only $290 principal. Equity starts at the $80,000 down payment and grows with every payment. The crossover — where principal first beats interest — arrives around year 19.

Equity, the crossover and PMI

Equity is your stake in the home: its value minus what you still owe. It grows two ways — as you pay the balance down, and, if you enter an appreciation rate, as the property itself gains value. The schedule’s equity column tracks both, and the headline stats show your equity after five years and, with appreciation, the projected value and equity at payoff.

Two milestones matter. The crossover month is when a payment first puts more toward principal than interest — on a long loan it arrives surprisingly late, and prepaying brings it forward. PMI, charged when you start below 20% down, drops off the moment your balance reaches 80% of the home’s value; enter a PMI rate and the calculator flags exactly when that happens.

Prepayments, dates, ARMs and the tax line

A prepayment comes straight off the balance, so every future month’s interest is charged on a smaller number. Add a recurring extra or a one-time lump and the schedule recomputes from that point — the balance drops faster, the crossover arrives sooner, and the loan finishes early, with the interest saved reported in the stats. Enter a start date and every row is dated, so you can see the actual calendar month each payment falls in.

For an adjustable-rate mortgage, set the reset rate and the fixed period and the calculator applies a single adjustment, recomputing the payment on the remaining balance and term. And for US taxpayers, the first-year interest is called out directly — the figure behind the mortgage-interest deduction — while the cumulative-interest column lets you read off any later year’s interest as the difference between two year-end rows.