Downloadable Amortization Schedule Calculator

Use this downloadable amortization schedule calculator to estimate a fixed-rate loan’s monthly payment and total interest from its principal, APR, and term. It also gives you the inputs and formula needed to build a payment-by-payment schedule you can save or export; the calculator itself summarizes the loan rather than generating a file.

Formula

The calculator uses the standard level-payment formula for a fully amortizing loan with monthly payments. It calculates the payment as:

Payment = P × r ÷ [1 − (1 + r)−n]

• P is the starting loan principal, in dollars.
• r is the monthly interest rate as a decimal: APR ÷ 12 ÷ 100. In the calculator expression, this is apr / 1200.
• n is the number of monthly payments: term in years × 12.
• Payment is the level monthly principal-and-interest payment, in dollars, before any separately charged amounts.

The displayed total interest is Payment × n − P. The payment and resulting interest are displayed to cents. Because this calculator’s payment expression is not rounded inside the formula before total interest is calculated, its total is a mathematical estimate; a real schedule typically rounds each payment and interest posting according to the lender’s method, and the final payment may be adjusted.

Worked Example

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

1. Convert the APR to a monthly decimal rate: 8 ÷ 1200 = 0.0066667.
2. Find the number of payments: 5 × 12 = 60.
3. Substitute into the payment formula: 20,000 × 0.0066667 ÷ [1 − (1.0066667)−60].
4. The monthly payment is approximately $405.53 when rounded to cents.
5. Using the unrounded payment in the calculator’s total-interest expression, total interest is approximately $4,331.82, displayed to cents.

The exact result can differ by a cent or more from a statement or lender-provided schedule because the calculator’s displayed payment is rounded while its interest calculation uses the formula’s unrounded payment.

Assumptions

• The interest rate is fixed for the entire term.
• Payments are equal monthly payments made at the end of each monthly period.
• Interest accrues monthly at APR divided by 12; the formula treats the APR as a nominal annual rate.
• The estimate includes principal and interest only. It excludes fees, taxes, insurance, PMI, escrow, and other amounts unless they are incorporated into the principal or supplied separately.

What a Downloadable Amortization Schedule Shows

An amortization schedule lays out how each payment is allocated over time. A full schedule commonly has one row per payment period and columns for the payment number or date, opening balance, payment amount, interest portion, principal portion, and closing balance. Early in a fully amortizing loan, interest is calculated on a larger balance, so more of the regular payment goes toward interest. As the balance declines, the interest portion generally falls and more of the payment reduces principal.

For a sample row, if the opening balance is $20,000 and the monthly rate is 0.0066667, the first month’s estimated interest is about $133.33. With a payment of roughly $405.53, about $272.20 goes to principal, leaving a balance near $19,727.80. A real schedule may show slightly different cents because of the lender’s rounding and posting rules.

How to Make and Save a Schedule

This page’s calculator returns summary figures, not a downloadable spreadsheet or PDF. To create a complete table, calculate each period’s interest from the opening balance, subtract that interest from the payment to find principal repaid, then subtract principal repaid from the opening balance. Repeat until the balance reaches zero. A spreadsheet can automate the repeated rows and can be saved or exported in formats supported by the spreadsheet program.

1. Enter the original amount borrowed, APR as a yearly percentage, and term in years.
2. Use the calculator’s payment as a check against the amount used in your table.
3. For each period, calculate interest as opening balance × monthly rate.
4. Calculate principal as payment − interest, then closing balance as opening balance − principal.
5. Check the final row: the remaining balance should reach zero, subject to rounding and any final-payment adjustment.

Use the actual payment start date and payment amount if you need a dated schedule. The simple formula assumes regular monthly periods; it does not account for irregular first periods, daily interest conventions, payment holidays, or changes in the amount due.

Reading Results and Avoiding Common Errors

The monthly payment shown here is not necessarily the full amount due on a bill. A mortgage or other loan may have separate charges, and a loan with fees financed into the balance has a different principal from one where fees are paid separately. Compare like with like: principal-and-interest estimates should not be mistaken for a complete monthly housing or borrowing cost.

• APR entry: Enter 8 for 8%, not 0.08. The formula converts the percentage to a monthly decimal.
• Term entry: The field is in years. Five means 60 monthly payments, not five payments.
• Rounding: Rounding every row to cents can make the final balance differ slightly from zero. A schedule may adjust its last payment.
• Extra payments: Additional principal payments change later balances and interest. They are not included in these outputs.
• Changing rates: A variable rate or payment change requires recalculating future rows; this fixed-rate estimate does not model that change.

Frequently Asked Questions

Can I download an amortization schedule from this calculator?
This calculator displays estimated monthly payment and total interest, but does not create a downloadable file. You can use its figures to check a schedule made in a spreadsheet or request the official schedule from the lender.

What information do I need to make a schedule?
You need the starting principal, interest rate, payment frequency, payment amount or term, and the rules used to post interest and payments. A dated table may also need the first payment date.

Why does my spreadsheet’s total interest differ?
Common causes include rounding each period, using a different day-count method, treating APR as an effective annual rate, or including fees and payment dates. Check that both calculations use the same assumptions.

Does the monthly payment include taxes or insurance?
No. The calculator estimates principal and interest only. Taxes, insurance, escrow, fees, and other charges are outside its formula.

Can I use the schedule if I make extra payments?
The basic estimate assumes the regular payment only. To model extra payments, recalculate each period using the actual additional amount applied to principal, while following the loan’s payment-posting terms.

This result is an estimate for educational purposes, and the lender’s disclosure gives the exact figures.

Related

• Amortization Schedule Using Payment Amount
• Amortization Schedule by Month: Payment and Interest
• Amortization Schedule Spreadsheet: Payment and Interest

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