Personal Loan Repayment Schedule Calculator

A personal loan repayment schedule calculator estimates your fixed monthly payment and total interest from the loan amount, APR, and term. Enter the figures shown in your loan offer to see the modeled cost over the full schedule; the result is an estimate, not a lender payoff statement.

Formula

The calculator uses the standard amortizing-loan payment formula. It assumes equal monthly payments, a fixed annual percentage rate (APR), and monthly interest accrual:

Monthly payment = round[P × r ÷ (1 − (1 + r)⁻ⁿ), 2]

• P is the amount borrowed, in dollars.
• r is the monthly interest rate as a decimal: APR ÷ 12 ÷ 100. With an 8% APR, r = 0.08 ÷ 12.
• n is the number of monthly payments: loan term in years × 12.
• round rounds the monthly payment to the nearest cent before calculating total interest.

Total interest = monthly payment × number of payments − principal. This is the interest implied by the rounded payment across the full term. The formula does not create a dated, line-by-line account statement, but it gives the level payment and total-interest estimate for the stated assumptions.

Worked Example

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

1. Convert the APR to a monthly decimal rate: 8 ÷ 1,200 = 0.0066667.
2. Convert the term to payments: 5 × 12 = 60 months.
3. Substitute into the payment formula: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰].
4. The unrounded payment is about $405.527; rounded to cents, the monthly payment is $405.53.
5. Total interest using that rounded payment is $405.53 × 60 − $20,000 = $4,331.80.

Assumptions

• The APR is fixed for the full term; a changing rate is not modeled.
• Payments are made monthly, with the first payment one month after the loan begins.
• Interest compounds monthly at APR ÷ 12. The APR is treated as the rate input, not recalculated from a separately disclosed fee structure.
• Fees, taxes, insurance, optional add-ons, late charges, and payment-date effects are not included.

What a Repayment Schedule Shows

A repayment schedule, often called an amortization schedule, divides each payment between interest and principal. Early in a standard loan, the outstanding balance is larger, so more of the payment goes toward interest. As principal falls, the interest charged each month generally falls too, and more of a level payment reduces the balance. The payment stays level in this calculator because the rate and required payment are assumed not to change.

For example, at the start of the default loan, monthly interest is approximately $20,000 × 0.08 ÷ 12, or $133.33. The rest of the $405.53 payment—about $272.20—reduces principal. In later months, interest is calculated on a smaller remaining balance. Small differences can appear in an actual lender schedule because of payment dates, day-count methods, rounding, or fees.

When to Use the Estimate

Use the calculator to understand how the amount borrowed, stated APR, and term combine mathematically. You can change one input at a time to see its effect: a longer term usually lowers the calculated monthly payment but means more scheduled payments; a higher APR raises the payment and, all else equal, total interest. These are arithmetic relationships, not a recommendation about which loan or term to choose.

For an estimate based on an offer, use the amount you would actually borrow, the APR given by the lender, and the repayment term in the disclosure. Do not substitute a general advertised rate or assume that an application will produce a particular APR. Get the applicable rate, fees, and payment details from the lender’s own documents.

Common Problems and Limits

• APR versus monthly rate: Enter APR as a yearly percentage, such as 8, not as 0.006667. The formula converts it to a monthly decimal rate internally.
• Years versus months: The term field is in years. A five-year loan is entered as 5; the formula converts it to 60 payments.
• Rounding: The monthly payment is rounded to cents, then multiplied by the number of payments for the total-interest estimate. A lender may adjust the final payment by a few cents to clear the balance exactly.
• Fees and proceeds: A lender may deduct or finance fees. If the amount received differs from the principal used to calculate payments, this calculator does not capture that difference or calculate a fee-inclusive APR.
• Extra payments: Additional principal payments can change the payoff date and interest paid. They are not included here, so the displayed total assumes only the scheduled level payments.
• Irregular or changing terms: The formula does not model variable rates, skipped payments, deferments, late payments, or a nonmonthly schedule.

The calculator’s total interest is the scheduled interest implied by its assumptions, not a guaranteed amount owed on a particular date. For a current payoff figure, the lender must account for payment history and accrued interest through the requested date.

Frequently Asked Questions

How do I calculate a personal loan monthly payment?
Convert APR to a monthly decimal rate by dividing it by 1,200, convert the term to months, and apply the amortizing-payment formula above. The calculator performs those steps and rounds the result to cents.

Does the calculator include fees?
No. It uses the loan amount, APR, and term only. Entering a fee as part of the principal may approximate a financed fee, but it will not reproduce every fee or APR calculation in a lender’s disclosure.

Why does a longer term reduce the monthly payment?
The principal is divided across more scheduled payments, so the calculated payment is generally smaller. Interest accrues for a longer period, however, which can increase total scheduled interest when the other inputs are unchanged.

Can I use this to find my exact payoff balance?
No. It estimates a full-term payment and total interest from the original inputs. An exact payoff amount depends on the account balance, payments already made, accrued interest, and the payoff date; request it from the lender.

What happens if I pay extra each month?
Extra payments may reduce principal faster and change total interest and payoff timing, depending on how the lender applies them. This calculator assumes the regular scheduled payment only and does not model extra-payment rules.

This result is an estimate; the lender’s disclosure gives the exact figures.

Related

• 50/30/20 Budget Calculator
• Debt-to-Income Ratio Calculator (DTI)
• Credit Card Payoff Calculator: Months to Pay Off 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 | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2