Amortization Calculator
Build a dated, month-by-month schedule for a new fixed-rate loan, then trace each payment's principal and interest, remaining balance, yearly totals, and estimated payoff month.
Amortization Calculator
60 scheduled payments, paid off by Aug 2031.
Educational estimate only. Assumes a new fixed-rate loan, monthly interest and payments, and extras applied to principal. Excludes exact due dates, daily interest, fees, variable rates, missed payments, and lender-specific rules.
How it works
Formula and steps
The formula shows how the amortization calculator turns your inputs into the result. Use it to check the calculation, then follow the example steps to see each part of the math.
Formula & steps
Monthly payment formula
Use this to calculate the fixed monthly payment before building the schedule.
M= Monthly paymentP= Loan principalr= Monthly interest rate as a decimaln= Total number of monthly paymentsMonthly interest formula
I_t = B_(t-1) x r
Calculate each month's interest from the balance before that payment.
I_t= Interest charged for payment period tB_(t-1)= Remaining balance before the paymentr= Monthly interest rate as a decimalRemaining balance formula
B_t = B_(t-1) - P_t - E_t
Update the balance after scheduled and extra principal are applied.
B_t= Remaining balance after payment period tB_(t-1)= Remaining balance before the paymentP_t= Scheduled principal paid in the periodE_t= Optional extra principal paid in the period- 1Convert the annual interest rate to monthly rate r and the loan term to payment count n.
- 2Calculate fixed monthly payment M from principal P, rate r, and count n. At 0%, use P / n.
- 3For each row, multiply the opening balance by r to find that month's interest.
- 4Subtract interest from scheduled payment to find scheduled principal, then add any entered extra principal.
- 5Subtract scheduled and extra principal from opening balance; carry that result into the next row.
- 6Cap the final payment at the amount owed, then sum rows for total interest, total paid, yearly chart values, and payoff month.
Worked examples
$200,000 fixed-rate loan at 6.5% for 30 years
- 1
Convert rate and term
6.5% / 12 = 0.541667% monthly 30 x 12 = 360 payments
- 2
Calculate scheduled payment
M = $1,264.14 per month
- 3
Calculate first row
Interest = $1,083.33 Principal = $180.80 Ending balance = $199,819.20
Read payment 120 from same amortization schedule
- 1
Calculate interest from opening balance
Interest = $920.27
- 2
Find scheduled principal
$1,264.14 - $920.27 = $343.87 principal
- 3
Update remaining balance
Balance after payment 120 = $169,552.25
Common uses
- Inspect every monthly principal and interest split
- Use an amortization chart calculator to trace remaining balance
- Compare yearly principal and interest totals
- Create a calendar labeled from the first payment month
- Model recurring extra principal in a new-loan schedule
Common mistakes
- Looking only at the monthly payment instead of the principal and interest split over time.
- Adding rounded displayed rows and expecting exact agreement; the engine keeps full precision until values are formatted.
- Forgetting that extra payments reduce future interest only when the lender applies them to principal.
- Starting with a current balance and original loan term when the goal is remaining-loan payoff analysis.
- Treating the schedule as a lender statement or payoff quote instead of an estimate from the values entered.
- Assuming month and year labels represent exact due dates, daily-interest accrual, or lender processing rules.
Amortization schedule example
This example uses the same calculation engine as the interactive calculator: $200,000 principal, 6.5% fixed annual interest, 30 years, no extra payments, and a first payment in October 2026.
- Monthly payment
- $1,264.14
- Total interest
- $255,088.98
- Estimated payoff
- Sep 2056
| Payment | Date | Interest | Principal | Balance after payment |
|---|---|---|---|---|
| 1 | Oct 2026 | $1,083.33 | $180.80 | $199,819.20 |
| 60 | Sep 2031 | $1,015.47 | $248.67 | $187,221.95 |
| 120 | Sep 2036 | $920.27 | $343.87 | $169,552.25 |
| 360 | Sep 2056 | $6.81 | $1,257.33 | $0.00 |
The payment remains $1,264.14, but its split changes: payment 1 applies $1,083.33 to interest and $180.80 to principal; payment 120 applies $920.27 to interest and $343.87 to principal.
Amortization guide
How to read an amortization table and chart
This schedule starts with principal, fixed rate, and full term for a new-loan estimate. Use monthly rows and charts together to see how each payment reduces balance; use the main loan calculator for a compact payment comparison.
Read each monthly table row
Each row begins with the previous row's ending balance. Interest equals that opening balance times the monthly rate. Scheduled principal equals payment minus interest; optional extra principal reduces balance again. Payment includes interest, scheduled principal, and extra principal.
Why the payment split changes
On a fully amortizing fixed-rate loan, scheduled principal-and-interest payment stays level. Interest is larger early because balance is larger. As principal lowers balance, later interest falls and more of the same payment goes to principal.
Compare the amortization charts
The remaining-balance line follows the schedule month by month. Yearly bars sum scheduled principal, extra principal, and interest from the monthly rows. The final balance for each year matches the last monthly row included in that year.
Use the month-by-month payoff calendar
The selected first payment month and year label every row through the estimated payoff month. This calendar does not choose an exact due day or adjust for weekends, holidays, daily interest, or lender processing rules.
Understand rounding
The engine carries full-precision values through the schedule and rounds currency only for display. Adding displayed cents across many rows can therefore differ slightly from a total computed before formatting. The final payment is capped at the remaining modeled amount.
Choose payment estimate or payoff analysis
Use this page to inspect a new fixed-rate schedule in detail. Use the main loan calculator to compare payment and total cost from original loan terms. A future payoff calculator will instead start with current balance and known monthly payment.
Estimate a loan payment and total cost →Understand the estimate's limits
The model assumes a fixed annual rate, monthly interest, regular monthly payments, and recurring extras applied to principal. Adjustable rates, fees, taxes, escrow, biweekly schedules, irregular lump sums, missed payments, and lender-specific methods can produce different results.
FAQ
An amortization schedule shows each loan payment, how much goes to interest, how much reduces principal, and the remaining balance after the payment.
Interest is calculated from the current balance each month. The rest of the payment reduces principal, so later payments usually include less interest and more principal.
The calculator applies the same entered extra amount to principal each month. A lower balance produces less later interest and can shorten the schedule. Confirm principal-payment and prepayment rules with your lender.
Calculations keep full precision, while each displayed value is rounded to cents. Adding individually rounded rows can create a small difference from totals calculated before display rounding.
The balance chart shows how the estimated loan balance falls each month, while the yearly chart shows how payments are divided between principal and interest.
Yes, for a month-by-month estimate. Choose the first payment month and year to label the schedule, but note that the calculator does not model an exact day of the month, daily interest, holidays, or lender due-date rules.
Not necessarily. This estimator uses the values you enter and standard fixed-rate monthly math. A lender may use different rounding, exact payment dates, fees, or servicing rules.
You can estimate a schedule from a balance, rate, and remaining term, but this calculator derives a new scheduled payment. It is not designed to start from your known current payment or produce an exact lender payoff quote.
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