Loan Amortization Calculator

What a schedule shows that a payment figure hides

A loan calculator returns one number. An amortisation schedule returns the whole story: for every single payment, how much goes to interest, how much reduces the balance, and what is left. That table is what you need to answer the questions that actually come up — how much will I still owe when I want to sell, how much interest have I paid this tax year, what does the balance look like if I overpay from month 30.

The crossover point

Every amortising loan has a month where the principal portion first exceeds the interest portion. On a 30-year loan at 6 percent that arrives around year 18. Before it, most of what you pay is rent on the money; after it, most is genuinely buying the asset. The crossover moves earlier at lower rates and later at higher ones, and it is the single most revealing number in the table.

Reading the balance column

The balance after N payments is what you would need to repay to clear the loan, and it is the figure that determines equity in a sale. People are routinely surprised: five years into a 30-year mortgage the balance has fallen by roughly 7 percent, not the 17 percent that a linear intuition suggests. Any decision that assumes steady equity accrual — a planned move, a remortgage at a target loan-to-value — needs the actual schedule.

Modelling overpayments properly

A lump sum applied at month 12 does not simply shorten the loan by its face value. It removes that principal and every future interest charge that principal would have generated, so the saving is several times the payment on a long loan. Regular small overpayments compound similarly. A schedule is the only way to see this clearly, because the effect depends entirely on when the money lands.

Extra payments must be applied to principal

Send extra money without instruction and some servicers apply it to the next scheduled payment instead of the balance. That advances your due date but saves almost no interest — the opposite of the intent. The instruction to give is explicitly "apply to principal", and the next statement should be checked to confirm the balance dropped by the full amount.

Interest paid per year

Where mortgage interest is deductible, the annual interest total comes straight from the schedule and can be projected years ahead. It also falls every year, which means a deduction sized on year one is not a reliable assumption for year ten.

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