Amortization Calculator
A free amortization calculator that builds the full loan amortization schedule for any fixed-rate loan — principal, interest, and remaining balance for every payment, with optional biweekly and extra payments.
Loan Amortization Schedule Calculator
Principal vs interest over time
Amortization schedule
| Month | Payment | Principal | Interest | Remaining balance |
|---|
How to read an amortization schedule
An amortization schedule is a payment-by-payment table that shows exactly how a fixed-rate loan is paid off. Each row of the amortization table lists one payment split into two parts — the interest charged that period and the principal that actually reduces what you owe — followed by the remaining balance. The amortization calculator above produces the whole schedule the moment you enter a loan amount, rate, and term, so you can see every line from the first payment to the last.
Reading it is straightforward. Early payments are mostly interest because the balance is large; as the balance shrinks, more of each payment goes to principal. The chart turns the same data into an amortization chart calculator view, so you can watch the principal and interest shares trade places over time. Whether you call this an amortization table calculator, an amortization schedule calculator, or simply a loan payment calculator, it is the same loan amortization schedule under the hood — a complete loan payment schedule calculator and loan repayment schedule calculator that lays out where every dollar goes. If you came here to find amortization calculator results for an existing loan, set the start date to when the loan began.
Amortization formula
The fixed payment for an amortizing loan comes from the standard amortization formula:
where M is the payment per period, P is the loan amount, r is the periodic interest rate (the annual rate divided by the number of payments per year), and n is the total number of payments. This loan amortization formula is the same amortised loan formula used by banks worldwide; it is the engine behind the amortization calculator formula on this page.
Once the payment is fixed, each period is split in two: the interest for the period is the current balance times r, and the principal is whatever is left of the payment. Subtract that principal from the balance and repeat. Applying this accumulated-balance method down every row is what generates the full schedule above.
Biweekly vs monthly payments
With monthly payments you make 12 payments a year. A biweekly schedule pays half the monthly amount every two weeks, which works out to 26 half-payments — the equivalent of 13 monthly payments — each year. That one extra payment goes entirely to principal, so the balance falls faster, the term shortens, and you pay less total interest, all without a large change to your budget.
Switch the payment frequency to biweekly above and the tool acts as a biweekly mortgage calculator for a home loan, or the same accelerated schedule for a car loan or personal loan. The results show the shorter payoff and the lower interest side by side with what a monthly schedule would cost, so the trade-off is easy to see. Use it on a mortgage and it doubles as a dedicated biweekly mortgage calculator; the math is identical for any fixed-rate loan.
How extra payments save interest
Because interest is charged on the outstanding balance, any extra payment that goes straight to principal removes interest from every payment that follows. Add a recurring extra amount or a single lump sum and the schedule recomputes, showing how many payments you cut and how much interest you avoid. Even a modest monthly extra can shave years off a long loan.
On a home loan this makes the tool an extra mortgage payment calculator and a paying off home loan early calculator in one: enter your overpayment and compare the new payoff date and interest total against the original schedule. The savings summary states the difference plainly — in months saved and dollars of interest avoided — with no advice attached. As an extra mortgage payment calculator it simply shows the numbers; the decision stays yours.
How to build an amortization schedule in Excel
You can recreate this loan amortization schedule excel-style in a spreadsheet. Use the PMT function for the payment, then build one row per period: interest is the previous balance times the periodic rate, principal is the payment minus that interest, and the new balance is the previous balance minus the principal. Drag the formulas down for every period and the balance reaches zero on the final row.
That excel amortization schedule mirrors exactly what this page computes. The amortization formula excel users rely on is the same M = P × r (1 + r)ⁿ / ((1 + r)ⁿ − 1) shown above, just wrapped in PMT. A spreadsheet works as an amortisation table calculator, but it has to be rebuilt whenever the amount, rate, or term changes — the calculator here updates instantly and adds the chart and extra-payment comparison for free.
Related calculators
This is a general loan amortization tool. For a home purchase that also factors in property tax, insurance, and PMI, use our mortgage calculator. For financing a vehicle with a down payment, trade-in, and sales tax, see the car loan calculator. Both produce their own amortization schedule, while this page focuses on the schedule itself for any fixed-rate loan.