Amortization calculator

Any loan, laid out year by year: how much of each year’s payments went to interest, how much to principal, and what remains - built from the same month-by-month arithmetic the lender uses.

Loan amount ($)

Interest rate (% p.a.)

Term (years)

Extra per month ($, optional)

Anything above the required payment - every dollar of it goes straight to principal and shortens the schedule below.

Or: pay it off in this many years

Set a target instead of an amount, and this works out the extra payment that gets you there exactly.

Why are early payments mostly interest?

Early payments are mostly interest because interest is charged on the whole outstanding balance, and early on the balance is nearly the whole loan. On $300,000 at 6.5% over 30 years the payment is $1,896.20 a month; in year one roughly $19,340 of the $22,754 paid is interest, and the crossover - the first year in which more goes to principal than interest - does not arrive until well past the halfway mark. Watching the balance column is the clearest cure for underestimating what a mortgage costs.

Why does an extra dollar do more good early than late?

Because every extra dollar comes straight off the balance that interest gets charged on for the entire rest of the loan - pay it in year one and it saves interest every single month from then until the loan ends. Pay the same dollar in the final year and there is barely any "rest of the loan" left for it to save anything on. That is also why the "principal first exceeds interest" line above moves so much when the extra payment field is used: it is not just paying the loan off sooner, it is changing the shape of every payment that comes after it.

What conventions does this schedule use?

Monthly compounding, level payments, no fees or extras - the standard amortizing loan. Rounding is done at display time, so the final year absorbs the few cents of drift instead of hiding them. This page already handles extra payments directly - use the field above to see what they do to the schedule. For offsets and interest-only periods, the loan & mortgage calculator covers those.