Loan Payoff Graph: See Your Balance Over Time

A loan payoff graph shows how a loan balance is expected to fall as payments are made, and how much of each payment goes to interest versus principal. Enter the original loan amount, APR, and term to see an estimated monthly payment and total interest; this calculator summarizes the level-payment arithmetic rather than drawing a chart.

Formula

This calculator uses the standard fixed-rate, level-payment loan formula. It calculates the monthly payment as PMT = P × r / [1 − (1 + r)⁻ⁿ], then calculates total interest as I = PMT × n − P. Here, P is the amount borrowed in dollars, r is the monthly interest rate as a decimal (APR ÷ 1,200), and n is the total number of monthly payments (loan term in years × 12). APR is entered as a percentage per year.

The displayed payment is rounded to cents. The total-interest output uses that rounded payment multiplied by the number of payments, then subtracts the original principal. A real lender’s final payment may differ slightly because of payment dates, daily interest calculations, rounding rules, fees, or other contract terms.

Worked Example

Using the calculator’s default inputs—$20,000 principal, 8% APR, and a 5-year term—the monthly rate is 8 ÷ 1,200 = 0.0066667 and the number of payments is 5 × 12 = 60.

1. Monthly payment before rounding: $20,000 × 0.0066667 ÷ [1 − (1 + 0.0066667)⁻⁶⁰] ≈ $405.53.
2. Monthly payment rounded to cents: $405.53.
3. Total of the scheduled payments: $405.53 × 60 = $24,331.80.
4. Estimated total interest: $24,331.80 − $20,000 = $4,331.80.

Assumptions

• The interest rate stays fixed for the full term.
• Payments are equal and made monthly, with the first payment one month after borrowing.
• Interest is modelled monthly at APR ÷ 12.
• Fees, taxes, insurance, PMI, escrow, late charges, and payment-date effects are not included.

How to Read a Loan Payoff Graph

A payoff graph usually plots time along the horizontal axis and the remaining principal balance along the vertical axis. At the start, the balance is near the amount borrowed. With regular payments, the line trends downward and reaches zero at payoff. Some graphs also include separate bars or lines for principal paid and interest paid.

The balance line generally drops more slowly early in a level-payment loan because interest is calculated on a larger outstanding balance. As principal is repaid, less interest accrues each month, leaving more of the same payment to reduce principal. This pattern is called amortization. It does not mean the lender changes the scheduled payment; for a fixed-rate level-payment loan, the amount is generally steady while its principal-and-interest split changes.

This page provides payment and total-interest figures that can be used to interpret or build a basic payoff graph, but it does not generate month-by-month plotted points. To plot a balance after payment k, the common fixed-rate formula is B_k = P(1 + r)^k − PMT × [(1 + r)^k − 1] ÷ r. The result is the estimated principal balance after k monthly payments. A graph made from actual account statements may differ from this idealized curve.

What Changes the Shape of the Payoff

• Starting balance: A larger principal generally raises the payment and total interest when APR and term are unchanged.
• APR: A higher entered APR increases the interest portion under this formula. Use the APR supplied for the loan being modelled, rather than assuming a market rate.
• Term: A longer term spreads repayment across more months. It often lowers the scheduled monthly payment while increasing the total interest in a fixed-rate comparison with the same principal and APR.
• Extra payments: Additional principal payments can alter the balance path and may shorten repayment, but this calculator does not model them. The effect depends on how the servicer applies extra money and the loan’s terms.

For example, a graph with a steep early decline may reflect a shorter term, a higher payment, or extra principal payments. The curve alone does not reveal which explanation applies. Check the graph’s assumptions and whether it shows principal only or combines principal and interest.

Limits and Common Sources of Difference

A payoff graph is a projection, not a guarantee of the account balance on a future date. The calculation assumes equal monthly payments, fixed APR, and regular timing. Adjustable rates, deferred payments, skipped or late payments, daily interest accrual, fees added to the balance, and payment changes can all make a real repayment schedule depart from the projection.

One common misconception is that the APR is the monthly rate. It is an annual percentage; this calculator divides it by 12 to estimate the monthly periodic rate, so an 8% APR is entered as 8, not 0.08. Another common source of confusion is total payments versus total interest: the total of payments includes the amount borrowed, while interest is the amount above principal under the model. Small cent-rounding differences may accumulate across many payments.

For a loan already in progress, enter the current principal balance and the remaining term only if you want a simplified estimate from today onward. Using the original loan amount and original term instead describes the scheduled loan from its start, not the current payoff situation. A lender’s payoff quote may include accrued interest through a particular date and other contract-specific amounts that are not represented here.

Frequently Asked Questions

What does a loan payoff graph show?
A typical graph shows the estimated remaining loan principal over time. Some versions also break payments into principal and interest, so check the labels and assumptions.

Why does the balance fall slowly at first?
With level monthly payments, interest is calculated on the outstanding balance. Early in repayment that balance is larger, so more of each payment goes to interest and less to principal.

Does this calculator create a visual graph?
No. It calculates an estimated monthly payment and total interest, which can help explain a payoff graph. It does not output monthly balances or draw a chart.

Can I use it for a loan I already have?
For a simplified forward estimate, use the current principal balance and remaining term, along with the applicable APR. The result may differ from the lender’s account schedule or payoff quote.

Does the estimate include extra payments or fees?
No. It assumes scheduled, equal monthly payments and excludes extra payments and fees. Those items can change the repayment timeline and total cost.

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

Related

• Home Loan APR: What It Means and How It Works
• Home Equity Loan APR: How It Affects Your Payment
• Home Equity Loan APR Calculator and Payment Guide

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