$100K Home Equity Loan Calculator: Payment and Interest

A $100,000 home equity loan calculator estimates the monthly payment and total interest for a fixed-rate loan using the amount borrowed, APR, and repayment term. Enter the lender’s quoted figures to see the estimated payment and interest; the example below uses a 5-year term and an 8% APR.

Formula

The calculator treats the loan as a series of equal monthly payments at a fixed annual percentage rate. First convert the APR to a monthly rate, then apply the standard amortizing-payment formula:

• Monthly rate: r = APR / 1,200, where APR is entered as a percentage per year.
• Number of payments: n = years × 12.
• Monthly payment: Payment = round[P × r / (1 − (1 + r)⁻ⁿ), 2].
• Total interest: Interest = (rounded monthly payment × n) − P.

P is the principal, or amount borrowed, in dollars; r is the monthly interest rate as a decimal; n is the number of monthly payments; and the payment and total interest are in dollars. The payment is rounded to cents before total interest is calculated, so the displayed result follows the calculator’s payment-rounding assumption. Actual account statements can differ slightly because of payment dates, lender calculations, and final-payment adjustments.

Worked Example

Using the default inputs—$100,000 principal, 8% APR, and 5 years:

1. Convert the APR: 8 / 1,200 = 0.0066667 per month.
2. Calculate the number of payments: 5 × 12 = 60.
3. Substitute the values: $100,000 × 0.0066667 / [1 − (1.0066667)⁻⁶⁰].
4. Round the resulting monthly payment to cents: $2,027.64 per month.
5. Calculate total interest using that rounded payment: $2,027.64 × 60 − $100,000 = $21,658.40.

The payment covers both interest and principal. Early in a level-payment loan, interest makes up a larger share of each payment; as the balance declines, more of each payment goes toward principal.

Assumptions

• The APR and payment amount remain fixed for the full term.
• Payments are made monthly, with the first payment one month after borrowing.
• Interest compounds monthly at APR / 12.
• The estimate excludes lender fees, taxes, insurance, escrow, and any costs not entered in the calculator.

What a $100,000 Home Equity Loan Is

A home equity loan is generally structured as a lump-sum loan secured by a borrower’s home. The borrower receives the principal and repays it through scheduled installments. The home’s equity is the difference between its value and debts secured by it, but a $100,000 loan amount by itself does not establish whether someone qualifies or how much equity is available. Lenders assess their own requirements and provide the applicable terms.

Do not confuse a home equity loan with a home equity line of credit (HELOC). A loan typically provides a fixed amount at the outset and may have a fixed payment schedule. A HELOC is a credit line that can generally be borrowed from over time, and its payment calculation may depend on the balance, rate structure, and draw or repayment phase. This calculator is for a fully drawn, fixed-rate installment loan, not a HELOC.

How to Use the Estimate

• Loan amount: Enter the principal the lender would finance, not the home’s estimated value or equity.
• APR: Enter the quoted annual percentage rate. Do not substitute a monthly rate or enter 8 for 8 basis points; the input expects a percentage such as 8.
• Term: Enter the repayment period in years. A different term changes both the monthly payment and the number of months over which interest accrues.

Use the payment as an estimate of scheduled principal and interest, not as a complete household budget. Compare the result with the lender’s written payment schedule and ask which items are included in its quoted payment. If the lender’s APR or term differs from the calculator inputs, the estimate will not match its figures.

Costs, Limitations, and Common Mistakes

The displayed total interest is not the total cost of borrowing if separate charges apply. Fees, optional products, late charges, and other account-specific amounts are outside this formula. The calculator also assumes regular payments at the same interval and does not model extra payments, skipped or late payments, a changing rate, or an unusual first payment date.

• Mixing up APR and monthly rate: Enter APR as a yearly percentage. The formula divides it by 1,200 to obtain a monthly decimal rate.
• Using the home value as the loan amount: Use the amount actually borrowed. Home value and loan principal are different quantities.
• Ignoring term length: A longer term generally spreads repayment across more installments; it can lower the scheduled payment while changing cumulative interest.
• Expecting exact lender figures: Rounding, payment dates, fees, and contract terms may affect the amount due or final payment.

The formula is not an approval or affordability test and does not calculate available equity, underwriting outcomes, or property-related costs. It also cannot determine the rate, fees, or terms a lender will offer. Obtain those figures directly from the lender and review the written disclosures before relying on a payment estimate.

Frequently Asked Questions

What is the payment on a $100,000 home equity loan?
It depends on the APR and term. With the example inputs of 8% APR and 5 years, the estimated principal-and-interest payment is $2,027.64 per month.

How much interest would I pay on a $100,000 loan?
At the example’s 8% APR over 5 years, estimated interest totals $21,658.40 using a $2,027.64 rounded payment for 60 months. Your result changes with the APR, term, and lender’s calculation method.

Is a home equity loan payment fixed?
A fixed-rate loan with scheduled level payments is generally designed to keep its principal-and-interest payment consistent. This calculator assumes that structure; check the loan documents for the actual rate and payment terms.

Does this calculator include fees or taxes?
No. It estimates principal and interest only. It does not include fees, taxes, insurance, escrow, or other charges unless separately reflected in the lender’s figures.

Can I use this for a HELOC?
Not reliably. A HELOC can involve a changing balance or rate and different repayment phases, while this calculator assumes a fully borrowed lump sum repaid in equal monthly installments at a fixed APR.

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

Related

• Home Equity Loan Calculator: Amount Up to a CLTV Limit and Payment
• Mortgage Calculator With Escrow: Payment With Tax and Insurance
• Mortgage Loan Amount Calculator: The Loan a Monthly Payment Repays

in p | Loan amount | $ | 100000 | 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