Free Loan Amortization Schedule Calculator

This free loan amortization schedule calculator estimates a fixed-rate loan’s monthly payment and total interest from the amount borrowed, APR, and term. Its schedule shows how each monthly payment is divided between interest and principal, and how the balance declines over time.

Formula

The calculator uses the standard fixed-payment loan formula. It converts the annual percentage rate (APR) to a monthly rate, then calculates the level payment that pays down the balance over the selected number of months:

• Monthly rate, r = APR ÷ 1,200, where APR is entered as a percentage per year.
• Number of payments, n = loan term in years × 12.
• Monthly payment = P × r ÷ [1 − (1 + r)⁻ⁿ].
• Total interest = monthly payment × n − P.

P is the starting principal in dollars, r is the monthly interest rate as a decimal, and n is the number of monthly payments. The payment result is rounded to cents before total interest is calculated, so the displayed totals reflect that rounded payment. The formula assumes the same rate and payment amount throughout the term.

Worked Example

Using the calculator’s defaults: a $20,000 loan, 8% APR, and a five-year term.

1. Convert APR to a monthly rate: 8 ÷ 1,200 = 0.0066667, or about 0.66667% per month.
2. Find the number of payments: 5 × 12 = 60.
3. Substitute into the payment formula: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰] = approximately $405.53 per month, rounded to cents.
4. Calculate total interest using the rounded payment: $405.53 × 60 − $20,000 = $4,331.80.

These figures are estimates under the stated assumptions. A lender’s actual payment schedule can differ if the loan has fees, a different payment date convention, a variable rate, or other charges.

Assumptions

• The rate is fixed for the full term.
• Payments are equal monthly payments made at the end of each monthly period.
• Interest compounds monthly at APR divided by 12.
• Fees, taxes, insurance, private mortgage insurance, and escrow are not included.

How an Amortization Schedule Works

An amortization schedule is a month-by-month accounting of payments, interest, principal, and remaining balance. For each period, interest is generally calculated on the outstanding principal. The payment first covers that period’s interest; what remains reduces principal. In early payments, the balance is larger, so more of the payment goes toward interest. As principal falls, the interest portion usually gets smaller and the principal portion larger.

For example, at the start of the default loan, one month’s interest is approximately $20,000 × 0.0066667, or $133.33. Of a $405.53 payment, about $272.20 would therefore go to principal, leaving a balance near $19,727.80. Small differences may appear because displayed amounts are rounded, while lenders may calculate accrued interest using their own documented conventions.

This page calculates the regular payment and total interest, not a full downloadable row for every month. To construct a basic schedule, repeat the process for each payment: calculate interest on the current balance, subtract that interest from the payment to get principal repaid, then subtract principal repaid from the balance. The last payment may need adjustment to clear a small rounding remainder.

When to Use the Estimate

Use an amortization estimate to understand the relationship between loan amount, rate, and term, or to check the arithmetic in a quoted payment. Enter the principal you expect to finance rather than a property or vehicle’s price if a down payment or trade-in reduces the amount borrowed. Use the APR supplied for the specific loan offer; the 8% value here is only a calculator default, not a statement about available rates.

Read the payment and total interest together. A longer term spreads repayment across more months and, with the same rate and principal, generally produces a lower scheduled monthly payment but more total interest. A shorter term generally does the reverse. This comparison is mathematical only; the calculation does not account for a person’s budget, eligibility, or the full terms of a loan.

Common Errors and Limits

• Entering 8 instead of 0.08: Enter APR as a percentage, so 8 means 8% per year. The formula performs the conversion to a monthly decimal rate.
• Using the wrong principal: The loan amount is the amount financed, not necessarily the purchase price or current balance.
• Treating APR as every borrowing cost: APR is an input to this simplified formula; the calculator does not separately model fees or lender-specific cost calculations.
• Assuming every loan has level payments: Variable rates, interest-only periods, irregular payments, balloon payments, and payment holidays do not follow this standard schedule.
• Expecting exact lender figures: Payment dates, daily interest accrual, rounding, and additional charges can change the amount shown on a statement.

The formula is not suitable for a revolving credit balance or a loan whose payment or interest rate changes. It also does not account for extra payments. Extra principal payments can alter the balance path and payoff date, so a separate calculation using the lender’s rules is needed to estimate those effects.

Frequently Asked Questions

Is this loan amortization schedule calculator free?
Yes. The calculator estimates the regular monthly payment and total interest from the values entered. It does not require a paid calculation feature.

What information do I need for an amortization estimate?
Enter the amount financed, annual APR as a percentage, and loan term in years. For a closer estimate, use figures from the relevant loan disclosure and account for any charges separately.

Why does the interest portion shrink over time?
For a fixed-rate, level-payment loan, periodic interest is based on the remaining principal. As payments reduce the principal, less interest accrues in later periods, leaving more of each unchanged payment for principal.

Does the monthly payment include taxes and insurance?
No. This calculation covers principal and interest under its assumptions. Taxes, insurance, escrow, fees, and other charges require separate figures.

Can I use this for a variable-rate loan?
Not as a complete schedule. The formula holds APR constant for the entire term, while a variable rate can change and alter both payment amounts and interest over time.

Why might my lender’s payment differ?
The lender may use different rounding, payment timing, interest accrual, or included charges. Compare the estimate with the loan’s disclosure and ask the lender to explain any difference.

The result is an estimate, and the lender’s disclosure gives the exact figures.

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in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
out pmt | Monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2