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Mortgage & Real Estate

HELOC Payment Calculator

Interest-only draw period payments and full amortized repayment-period payments for a home equity line of credit.

Formula reviewed against standard interest-only and amortization formulas · Last checked Aug 2026 · methodology
Formula

How each phase is calculated

Draw: Payment = Balance × r
Repay: M = P × r(1+r)ⁿ ÷ [(1+r)ⁿ − 1]
rMonthly interest rate — annual rate ÷ 12
PBalance carried into the repayment period
nNumber of monthly payments in the repayment period
MFixed monthly payment during repayment
Worked example

$60,000 drawn at 8.5%, 10-year draw + 15-year repayment

Drawing $60,000 at 8.5% means interest-only payments of about $425/month for the entire 10-year draw period — roughly $51,000 in interest paid without touching the principal. Once repayment begins, the same $60,000 balance amortizes over 15 years at around $591/month, adding another $46,400 in interest before the balance reaches zero.

FAQ

Common questions

During the draw period, most HELOCs only require interest-only payments — you're paying the cost of borrowing but not reducing what you owe. Once the repayment period starts, the payment jumps to a fully amortizing payment covering both principal and interest, which is why many borrowers see a significant payment increase at that transition.

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