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How it works

Each month, interest is charged on the remaining balance. Extra monthly, yearly, or one-time principal shortens the term and cuts later interest. The last payment is adjusted so the balance is exactly zero.

interest_k = B_(k−1) · i · principal_k = A + extra_k − interest_k

When to use

Use this tool when you need to: default: {principal} at 6% for 15 years, monthly (~{payment}). Add extra payments to see earlier payoff.

How to use this tool

Enter your values in the fields above.
Review the formula and any mode options for your problem.
Read the result and the step-by-step solution.

Default: {principal} at 6% for 15 years, monthly (~{payment}). Add extra payments to see earlier payoff.

Frequently asked questions

What is the Amortization Calculator?: Each month, interest is charged on the remaining balance. Extra monthly, yearly, or one-time principal shortens the term and cuts later interest. The last payment is adjusted so the balance is exactly zero.
How do I use the Amortization Calculator?: Enter the required values, then calculate. The Amortization Calculator shows results, formulas, and step-by-step work when available. No account is required.
What formula does the Amortization Calculator use?: interest_k = B_(k−1) · i · principal_k = A + extra_k − interest_k

Browse categories

How it works

What is amortization?

Amortization has two common meanings. In lending, it is the systematic repayment of a loan with a fixed payment that covers interest first, then principal. In accounting, it is spreading the cost of a long-lived asset across the periods that benefit from it.

Paying off a loan over time

Mortgages, auto loans, and personal loans are usually amortized: you send the same payment each month. Early payments are mostly interest; later payments are mostly principal, because interest is charged only on what is still owed. Revolving credit such as a credit card is not amortized — the balance and the amount you repay can change every month. Interest-only and balloon loans also fall outside a standard amortization table.

Amortization schedule

The schedule lists every payment: interest for that month, principal applied, any extra, and the remaining balance. The annual table rolls those months into yearly totals. This tool models a fixed rate. Adjustable-rate loans, fees, and taxes are not included.

Extra payments

Extra monthly principal starts on the month you choose and is added to every payment after that. Extra yearly principal is applied once a year in the chosen month. One-time extras hit a single month. Extra principal does not change the scheduled payment — it reduces the balance faster, so the loan ends earlier and later interest is smaller.

Spreading costs

Businesses also use amortization to spread the cost of intangible assets — patents, licenses, franchises, customer lists — across their useful life, similar to depreciation of a building or machine. That accounting schedule is separate from loan repayment. This calculator is for amortizing a loan.

Frequently asked questions

What is the Amortization Calculator?

How do I use the Amortization Calculator?

Enter the required values, then calculate. The Amortization Calculator shows results, formulas, and step-by-step work when available. No account is required.