How to use Amortization Schedule Calculator
The amortization schedule calculator turns a loan into a full month-by-month payment plan. Enter the amount, interest rate, and term and it computes the fixed monthly payment, the total interest over the life of the loan, and a complete schedule showing how each payment splits between principal and interest. Add an optional extra monthly payment to see how much faster the loan clears, and download the whole schedule as a CSV.
- Enter the loan amount, annual interest rate, and term in years.
- Optionally add an extra monthly payment to accelerate payoff.
- Review the monthly payment, total interest, and first 12 months of the schedule.
- Download the full schedule as CSV using the download button.
Your data never leaves your device — 100% private processing.
How amortization works
Amortization is the process of paying off a loan with equal periodic payments. Each payment covers the interest accrued on the current balance first, with the remainder reducing the principal. Because the balance is largest at the beginning, early payments are interest-heavy; as the principal falls, more of each fixed payment chips away at the balance. Plotting the split over time produces the classic amortization curve, where the principal and interest portions cross over somewhere in the middle of the term for a typical mortgage.
| Month | Interest | Principal |
|---|---|---|
| 1 | $1,354 | $226 |
| 12 | $1,338 | $242 |
| 120 | $1,110 | $470 |
| 360 | $9 | $1,571 |
The power of extra payments
Because interest compounds on the remaining balance, paying even a small amount extra each month has an outsized effect over the life of a long loan. The extra goes straight to principal, which lowers every future interest charge and shortens the term. On a 30-year mortgage, an extra hundred or two per month can cut years off the loan and save tens of thousands in interest. The calculator’s extra-payment field lets you test different amounts and see the payoff time and total interest change immediately.
Worked examples
Home loan
Inputs: $250,000 · 6.5% · 30y
Result: $1,580/mo · ~$318,860 interest
Car loan
Inputs: $30,000 · 5% · 5y
Result: $566/mo · ~$3,968 interest
With extra $200/mo
Inputs: $250,000 · 6.5% · 30y
Result: Paid off years early, interest cut
Glossary
- Amortization
- Repaying a loan with scheduled equal payments that cover interest and reduce principal.
- Principal
- The outstanding loan balance on which interest is charged.
- Interest
- The cost of borrowing, charged as a rate on the remaining principal each period.
- Term
- The length of time over which the loan is scheduled to be repaid.
Related reading
Frequently Asked Questions
Why use Amortization Schedule Calculator?
- Builds a complete month-by-month schedule of principal, interest, and balance
- Shows the fixed monthly payment and total interest for the whole loan
- Models extra monthly payments to reveal faster payoff and interest savings
- Exports the full schedule to CSV for spreadsheets or record-keeping
Common use cases
- Plan a mortgage or car loan and see the true lifetime interest cost
- Decide whether making extra payments is worth it for a specific loan
- Check how much of an early payment goes to interest versus principal
- Export a payoff schedule to share with a co-borrower or advisor
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