Work out a home equity line of credit payment: interest-only while you draw, the higher payment when repayment starts, and the most a lender may let you borrow.
Rates here are editable examples, not today's rates. Use the rate from your own quote or Loan Estimate.
Estimates for planning, not financial, tax or legal advice. Figures use US rules unless the page says otherwise.
What this HELOC calculator does
A home equity line of credit (HELOC) has two stages. During the draw period you can borrow, repay and borrow again, and many plans let you pay only the interest. In the repayment period you can't draw any more and the balance is paid off in equal monthly payments. This page shows both payments, how big the jump is, and your credit limit.
How it's calculated
Credit limit = home value × max CLTV − mortgage balance
Draw-period payment = balance × rate ÷ 12
Repayment payment = B × i ÷ (1 − (1 + i)−n)
CLTV is the combined loan-to-value: everything secured by the home, divided by its value. B is the balance at the end of the draw, i is the rate ÷ 12, and n is the number of months to repay. The calculator assumes the balance and rate stay the same.
Worked example
A $500,000 home with a $300,000 mortgage and an 85% CLTV limit: 500,000 × 0.85 − 300,000 = $125,000 line. You draw $75,000 at 8.5%:
Draw: 75,000 × 0.085 ÷ 12 = $531.25 a month for 10 years
Repayment: $75,000 over 240 months at 0.7083% a month = $650.87 a month for 20 years
Total interest comes to $144,958, because nothing is repaid for the first 10 years.
Limitations
- Most HELOCs have variable rates tied to an index such as the prime rate, so your payment can change even if you don't borrow more. Try a higher rate to see the effect.
- Some lenders use an introductory rate for the first months. Use the rate that applies after it ends.
- Some plans don't fully repay the balance by the end and ask for a balloon payment. Check your agreement.
- The CLTV limit is set by each lender. 85% is just a starting value here, so change it to match your offer.
- Annual fees, closing costs and minimum draw amounts aren't included.
Sources
How we checked this
Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:
- $500,000 home, $300,000 owed, 85% CLTV: $125,000 line ✓
- $75,000 at 8.5%, interest-only draw: $531.25 ✓
- Then 20 years of repayment: $650.87 ✓
- No draw period, $50,000 at 9% over 15 years: $507.13 ✓
- Mortgage above the CLTV cap: no equity to borrow ✓
Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.
Questions people ask
How does a HELOC loan work?
A HELOC is a line of credit secured by your home. During the draw period, often around 10 years, you borrow what you need and often pay only interest on what you've used. Then the repayment period starts: you can't borrow more and you pay back principal and interest, so the payment goes up.
What is a HELOC?
A home equity line of credit lets you borrow against your home's equity, its value minus what you owe. Unlike a home equity loan, you don't get a lump sum. You draw money as you need it, up to a limit, and it usually has a variable rate.
How is an interest-only HELOC payment calculated?
Multiply the balance by the annual rate and divide by 12. $75,000 at 8.5% is 75,000 × 0.085 ÷ 12 = $531.25 a month. None of it reduces the balance.
What is the payment on a 10-year draw HELOC?
During the 10-year draw it's usually interest only. When repayment starts, the balance is spread over the repayment period. $75,000 at 8.5% over 20 years is $650.87 a month.
How much can I borrow with a HELOC?
Lenders cap the combined loan-to-value. Multiply your home's value by that limit and subtract your mortgage balance. At 85% on a $500,000 home with $300,000 owed, that's $125,000.