HELOC Payment Calculator
Estimate HELOC payments in the draw period and the repayment period, the payment jump when repayment starts, total interest and fees, how much you can borrow, and a full payment schedule.
How it works
Draw period (interest only): payment = balance × rate ÷ 12 · Repayment: M = P × i ÷ (1 − (1 + i)^−n) · CLTV limit: credit line = home value × max CLTV − mortgage balance
A HELOC has two phases. During the draw period (often 10 years) you can borrow against your equity and usually owe only the interest: the balance times the annual rate, divided by 12. Some lenders instead require a minimum percentage of the balance, which pays some principal each month; the calculator covers both, plus any extra principal you choose to pay. When the draw period ends, the line enters the repayment period: you can no longer borrow, and whatever is left amortizes into equal principal-and-interest payments M over n months at monthly rate i. That jump is the payment shock the calculator highlights. HELOC rates are usually variable and follow the prime rate, so the calculator lets you set a different rate for the repayment period and shows the payments one point lower and up to three points higher. Upfront closing costs and an annual fee during the draw period are added to the total cost. If you turn on the borrowing check, the credit line is estimated as the home value times the lender’s maximum combined loan-to-value (CLTV), minus what you still owe on the mortgage.
Worked example
Draw $50,000 at 8.5% with a 10-year draw period and a 20-year repayment period. Interest only is $50,000 × 0.085 ÷ 12 = $354.17 a month, so after 10 years you still owe $50,000 and have paid $42,500 of interest. Repayment then costs $433.91 a month for 20 years, $79.74 more than before, and adds $54,139 of interest, for $96,639 in total. Paying a 1% minimum plus $100 extra each month during the draw period instead cuts the balance to about $25,079 by the time repayment starts, so the repayment payment drops to $217.64 and total interest falls to about $58,534. On a $400,000 home with $250,000 still owed on the mortgage and an 85% CLTV limit, the credit line could be up to $90,000.
Sources: CFPB — What you should know about home equity lines of credit (HELOC) · CFPB — What is a home equity line of credit (HELOC)?
Frequently asked questions
Why does my payment jump after the draw period?
During the draw period you often pay interest only, so the balance never shrinks. When repayment begins, that whole balance must be paid off with principal over the repayment term, which sharply raises the monthly payment. The calculator shows the increase and the balance that is left when repayment starts.
Are HELOC rates fixed or variable?
Most are variable, tied to the prime rate plus a margin, so the payment rises or falls with prime. Use the “Rate change when repayment starts” option or the rate table to see how a higher rate would change your payments. Some lenders offer a fixed-rate lock on part of the balance.
Can I pay principal during the draw period?
Usually yes, and it helps. Enter an extra principal amount, or pick the “% of balance” payment type if your lender requires a minimum percentage. Paying down principal early lowers the balance that has to be repaid later, softens the payment jump and cuts the total interest.
How much can I borrow with a HELOC?
Lenders usually cap the combined loan-to-value (your mortgage plus the HELOC, divided by the home value) at 80%–90%. Turn on the borrowing check: the credit line is the home value times that limit, minus your mortgage balance. Your credit score, income and the lender’s own rules also matter.
What fees does a HELOC have?
Some lenders charge closing costs such as an appraisal or origination fee, and some charge an annual fee while the line is open. Many waive the closing costs if you keep the line open for a few years. Enter any fees to see the total cost of borrowing.
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This is an educational estimate, not financial advice. Lenders use their own rounding, fees and terms — confirm exact figures with your lender or a licensed advisor.