Amortization Calculator
Use this amortization calculator to build a full payment schedule for a fixed-rate loan and see how each payment is divided between principal and interest over time.
It is designed as a schedule-first tool rather than just a payment estimate. The goal is to help you track remaining balance, understand why early payments include more interest, and see how an optional extra monthly payment could shorten the loan and reduce total interest.
Results are planning estimates only. This amortization schedule assumes a fixed rate and regular monthly payments, but lender statements, escrow, fees, and servicing rules can vary.
How to use this calculator
- Enter the loan amount, interest rate, and loan term.
- Add the loan start month so the schedule can label each payment and payoff date.
- If you want to test faster payoff, enter an optional extra monthly payment.
- Calculate to review the monthly payment, payoff date, annual summary, and full amortization schedule.
- Compare the standard schedule with the extra-payment version to see how much interest and time may be saved.
This works well when you want to understand the shape of a loan over time, not just the payment amount at the start.
How it works
This calculator first estimates the standard fixed monthly payment, then builds a full amortization schedule showing how each payment is split between principal and interest.
It is designed to explain the shape of a loan over time, including the remaining balance path and the impact of an optional recurring extra monthly payment.
Monthly payment formula
Monthly payment = P × r × (1 + r)n / ((1 + r)n − 1)
Main inputs in the estimate
- P
- Loan amount, or the principal balance at the start of the schedule
- r
- Monthly rate derived from the annual interest rate
- n
- Total number of monthly payments in the original loan term
What the schedule assumes
- The schedule assumes a fixed interest rate and equal required monthly payments over the original term.
- Each month shows interest first, then the portion of the payment that reduces principal and remaining balance.
- If you enter an extra monthly payment, that amount is applied to principal every month until payoff.
- Taxes, insurance, fees, and escrow items are not part of this amortization schedule.
Assumptions and limitations
- This calculator models a fixed-rate loan with equal required monthly payments over the original term.
- The amortization schedule focuses on principal and interest only.
- Extra monthly payment is modeled as the same recurring extra amount every month.
- Taxes, insurance, escrow, late fees, and lender-specific servicing rules are not included.
Example scenario
Use this example to see how an amortization schedule can show both the normal loan path and the effect of a small recurring extra payment.
- Loan amount:
$300,000 - Interest rate:
6.5% - Loan term:
30 years - Loan start date:
Apr 2026 - Extra monthly payment:
$100
With those inputs, the standard monthly payment is about $1,896.20, while the planned payment with the extra amount is about $1,996.20.
The extra payment shortens the schedule from about 360 months to about 312 months, moving the estimated payoff date from Mar 2056 to Mar 2052. Here, the payoff date means the month of the final scheduled payment.
It also reduces total interest from about $382,633.47 to about $321,638.68, for estimated interest savings of about $60,994.79.
This is why an amortization calculator is useful even when you already know the payment: it helps you see where the money goes month by month and how the balance changes over time.
Frequently asked questions
What is an amortization schedule?
An amortization schedule is a payment-by-payment table that shows how much of each loan payment goes to principal, how much goes to interest, and what balance remains after each payment.
How is this different from a loan calculator?
A loan calculator usually focuses on the monthly payment, total paid, and total interest. An amortization calculator goes further by showing the full payment schedule and balance path over time.
Why do early loan payments include more interest?
Interest is charged on the remaining balance. Early in the loan, the balance is highest, so more of each payment goes to interest. As the balance falls, more of the payment goes to principal.
How do extra monthly payments affect amortization?
Extra monthly payments reduce principal faster, which can shorten the loan term and lower total interest. This calculator models a simple recurring extra payment each month.
Can I use this for mortgages and other fixed-rate loans?
Yes. It works for many fixed-rate loans, including mortgages, auto loans, and personal loans, as long as the loan uses regular monthly payments and a fixed interest rate.
Does this calculator include taxes, insurance, or fees?
No. This page focuses on the loan amortization schedule itself. Taxes, insurance, escrow, and fees are outside the amortization math in this version.
What happens if my interest rate is 0%?
If the rate is 0%, every payment goes to principal and the schedule becomes a straight-line payoff over the loan term.
Is this an exact lender statement?
No. It is a planning estimate. Real loan servicing can differ because of statement timing, escrow, fees, and lender-specific rules.
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