Home Equity Loan Balance Calculator and Formula

A home equity loan balance calculator estimates how much principal remains after a chosen number of monthly payments on a fixed-rate loan. Enter the original loan amount, annual interest rate, term, and payments made to see the estimated balance and related payment figures.

Formula

The balance calculation assumes a fixed interest rate and equal monthly payments. It applies the standard remaining-balance formula:

B = P(1 + r)^k − M × [(1 + r)^k − 1] ÷ r

• B is the estimated balance after the payments, in dollars.
• P is the original amount borrowed, in dollars.
• r is the monthly interest rate, calculated as APR ÷ 1,200. APR is entered as a percentage per year.
• k is the number of monthly payments already made.
• M is the monthly payment, rounded to the nearest cent. It is calculated as P × r ÷ [1 − (1 + r)⁻ⁿ].
• n is the full loan term in months, calculated as years × 12.

The calculator uses the rounded monthly payment in the balance formula. It also reports the payment amount and the total of those payments made so far, calculated as M × k. The added square-root check makes the result unavailable if the entered payments exceed the full term; it does not represent an extra loan charge.

Worked Example

Using the calculator’s default inputs—$50,000 borrowed, 8% APR, a 15-year term, and 24 monthly payments made:

1. Convert the term to months: 15 × 12 = 180 payments.
2. Calculate the monthly rate: 8 ÷ 1,200 = 0.0066667.
3. Calculate the scheduled payment: $50,000 × 0.0066667 ÷ [1 − (1.0066667)⁻¹⁸⁰] = approximately $477.83 per month, rounded to cents.
4. Apply the balance formula after 24 payments: $50,000 × (1.0066667)²⁴ − $477.83 × {[(1.0066667)²⁴ − 1] ÷ 0.0066667} = approximately $45,183.72.
5. Total of the 24 scheduled payments: $477.83 × 24 = $11,467.92.

The total paid is not the amount of principal reduced: part of each payment covers interest. The balance formula estimates the remaining principal under the stated assumptions.

Assumptions

• The interest rate remains fixed for the entire modeled term.
• Payments are equal, made monthly, and applied at the end of each monthly period.
• Interest compounds monthly using APR divided by 12.
• Fees, taxes, insurance, escrow, late charges, and additional principal payments are not included.

How to Use the Balance Estimate

Enter the original principal rather than the home’s value or the amount of equity you believe you have. Use the APR and term stated in the loan documents or lender’s estimate, and enter how many regular monthly payments have actually been made. If you are estimating a future date, count scheduled payments through that date; the result is not an official payoff quote.

A home equity loan is generally structured as a separate installment loan secured by home equity, with funds borrowed as a lump sum and repaid over time. This calculator models the arithmetic of a fixed-rate loan. It does not calculate available home equity, determine a borrowing limit, or estimate approval. Those questions depend on information and criteria the calculator does not have.

The number of payments must be no greater than the total number in the term. For example, a 15-year loan has 180 scheduled monthly payments. Entering 181 payments for that term makes the calculation invalid. A zero in the payments-made field represents the starting balance before any scheduled payment.

What Can Change the Actual Balance?

The estimate can differ from a servicer’s current balance when the actual loan has a variable rate, irregular payment dates, payment changes, skipped or late payments, or additional principal reductions. The calculator also assumes each payment is credited at the end of a monthly period. Actual interest accrual can depend on the loan’s payment and posting details.

• Extra payments: An additional amount applied to principal can reduce the balance faster than the regular-payment schedule shown here.
• Fees or unpaid charges: Charges that are added to an account are not represented in this principal-only formula.
• Rounding: The calculator rounds the scheduled payment to cents. A lender’s precise payment schedule can include its own rounding and posting conventions.
• Payoff amount: A payoff quote may account for interest accrued since the last payment and other account-specific items. It is not necessarily equal to the principal balance displayed by an estimate.

For an accurate account balance or payoff figure, use the loan statement or request the current figure from the loan servicer. To model a loan with extra principal payments or a changing rate, the payment history and rate schedule would need to be included explicitly.

Balance Versus Home Equity

A loan balance is the estimated amount of principal still owed under the modeled schedule. Home equity is a different quantity: it is commonly described as the home’s value minus debts secured by it. This calculator does not estimate home value or account for other liens, so it cannot calculate a household’s total equity. Home value can also be uncertain and may differ from a sale price or valuation used by another party.

Likewise, a low remaining balance does not by itself establish how much additional borrowing may be available. A lender would need to assess its own requirements and the property and borrower information it requests. The calculator provides no approval or borrowing-capacity estimate.

Frequently Asked Questions

How do I calculate the remaining balance on a home equity loan?
Use the original principal, monthly interest rate, scheduled monthly payment, and number of payments made in the remaining-balance formula shown above. For a fixed-rate loan with regular payments, it estimates principal remaining after those payments.

Does the calculator show my home equity?
No. It estimates the balance of one loan only. Estimating equity also requires a current home value and information about any other debts secured by the home.

Why is my statement balance different from this estimate?
Differences can result from payment timing, variable rates, extra or late payments, fees, accrued interest, or rounding. The formula uses a simplified fixed-rate monthly schedule and excludes account-specific charges.

Can I use this for a home equity line of credit?
This calculator is designed for a fixed-rate, installment-style loan with equal monthly payments. A line of credit may allow draws and repayments that change the balance, so its history and terms are not represented by this formula.

Is the remaining balance the same as the payoff amount?
Not necessarily. A payoff figure may include interest accrued through a specific date and other account-specific amounts. Ask the loan servicer for an exact payoff figure.

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

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in p | Original loan amount | $ | 50000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 15 | 0.0833 | 50
in k | Monthly payments made | - | 24 | 0 | 600
out bal | Estimated remaining balance | $ | p * (1 + apr / 1200) ^ k - round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) * ((1 + apr / 1200) ^ k - 1) / (apr / 1200) + 0 * sqrt(yrs * 12 - k) | 2
out pmt | Estimated monthly payment | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out paid | Payments made, total | $ | pmt * k | 2