Free Loan Calculator With Amortization Table

A free loan calculator with an amortization table estimates your monthly payment and total interest from the loan amount, APR, and term. Enter those figures to see the level payment and a month-by-month schedule showing how each payment is divided between interest and principal.

Formula

The monthly payment is calculated using the standard fixed-payment loan formula:

M = P × r / (1 − (1 + r)−n)

• P is the amount borrowed, in dollars.
• APR is the annual percentage rate entered as a percentage.
• r is the monthly rate, calculated as APR ÷ 1,200.
• n is the number of monthly payments, calculated as years × 12.
• M is the monthly payment, in dollars.

The calculator rounds the payment to cents for display. Total interest is estimated as the rounded monthly payment multiplied by the number of payments, minus the original principal: I = M × n − P. The amortization table is then produced by applying each payment to the balance: interest for a month is the outstanding balance multiplied by the monthly rate, and the remainder of that payment reduces principal.

Worked Example

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

1. Convert the APR to a monthly rate: r = 8 ÷ 1,200 = 0.0066667.
2. Find the number of monthly payments: n = 5 × 12 = 60.
3. Substitute into the payment formula: M = 20,000 × 0.0066667 ÷ (1 − (1.0066667)−60).
4. The unrounded payment is about $405.53, so the displayed monthly payment is $405.53.
5. Using that cent-rounded payment, estimated total interest is $405.53 × 60 − $20,000 = $4,331.80.

Assumptions

• The interest rate remains fixed for the entire term.
• Payments are equal, monthly, and made at the end of each monthly period.
• Interest is calculated monthly at APR divided by 12.
• The calculation excludes fees, taxes, insurance, PMI, and escrow; these are not inputs.

How to Read an Amortization Table

A typical schedule has one row per payment period. It may show the payment number or date, opening balance, payment amount, interest charged, principal repaid, and closing balance. In the first period, interest is calculated on nearly the full loan balance. As principal falls, the interest portion generally falls too, while more of the same payment goes toward principal.

For the example, first-month interest is approximately $20,000 × 0.0066667 = $133.33. Of the $405.53 payment, about $272.20 reduces principal, leaving a balance near $19,727.80. Actual schedule values can differ by a cent because lenders may calculate interest using their own day-count conventions, payment dates, and rounding practices.

The displayed total interest is an estimate based on the calculator’s rounded payment and stated assumptions. It is not the same as the monthly payment, and it does not necessarily equal a lender’s total cost figure. For a complete schedule, inspect each row and confirm that the ending balance reaches approximately zero after the final payment. Small residual differences can arise from rounding.

When to Use It and What It Leaves Out

This calculator is useful for understanding the basic payment pattern of a fixed-rate loan, estimating interest over the full stated term, and comparing hypothetical combinations of principal, APR, and duration. It gives a mathematical illustration, not a borrowing recommendation or a prediction of approval. Enter the rate and loan amount supplied in the relevant lender documents or quote; do not treat the example defaults as market rates.

The formula assumes one loan balance, an unchanged rate, equal monthly payments, and no extra payments. It does not model variable rates, a balloon payment, skipped or late payments, payment holidays, fees rolled into the balance, or daily interest calculations. It also does not include taxes, insurance, escrow, or other charges that may affect an actual bill. If a loan has those features, its schedule may differ materially from this simplified calculation.

Common Errors and Limits

• Entering APR as a decimal: Enter 8 for 8%, not 0.08. The formula converts the percentage to a monthly decimal rate.
• Confusing term units: The input is years. A five-year term becomes 60 payments, not five payments.
• Mixing payment and total cost: The monthly payment is not the total paid over the loan. Total payments include principal as well as interest.
• Ignoring rounding: A payment rounded to cents can make the final installment slightly different from earlier ones. A lender may adjust the last payment.
• Assuming all quoted costs are included: The calculator only uses principal, APR, and term. Check lender disclosures for charges or other amounts outside the model.

A common misconception is that every month’s payment goes toward principal. Under an interest-bearing amortizing loan, interest is charged on the unpaid balance first; only the remainder reduces principal. Extra principal payments can change the balance and future interest, but this calculator does not include them.

Frequently Asked Questions

Does this calculator show an amortization table?
A complete amortization table lists the payment-by-payment split between interest and principal and the remaining balance. This calculator’s inputs and outputs estimate the payment and total interest; use those figures with the monthly balance method described above to understand how the schedule is constructed.

How is an amortization payment calculated?
The fixed-payment formula uses the principal, monthly interest rate, and total number of monthly payments. It sets the payment so the loan balance is paid down over the stated term, assuming regular payments and no changes to the rate or schedule.

Why does the interest portion change each month?
Interest is calculated on the outstanding balance. As payments reduce principal, the balance used to calculate later interest becomes smaller, so a larger share of a level payment can go toward principal.

Is APR the same as the monthly interest rate?
No. In this estimate, the APR percentage is divided by 12 to obtain a monthly rate, with an additional division by 100 to convert percentage points to a decimal. The APR entered may not capture every charge associated with a loan.

Why might a lender’s payment differ?
The actual loan may include fees, a different balance or rate, variable interest, different payment dates, or a calculation method that handles daily interest and rounding differently. Compare the calculator assumptions with the lender’s disclosed schedule.

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

Related

• Home Loan Amortization Table: Payments and Balance
• House Amortization Table: Monthly Payment and Balance
• Car Loan Amortization Table Calculator

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