HELOC Calculator

Estimate how large a home equity line of credit you could qualify for, and what your payments would be during the draw period and after it ends.

Most lenders allow 80–85% of your home's value across all loans.

Estimated maximum credit line
$132,500
Your equity
$200,00044% of the home's value
Interest-only payment during the draw period
$343.75
Payment during repayment
$426.03
Total interest over the loan
$93,497.88
  • HELOC rates are usually variable, so payments change when the prime rate moves. Figures assume today's rate for the whole loan and that the full amount is borrowed at the start.

How a HELOC works

A home equity line of credit lets you borrow against the part of your home you own outright. It works like a credit card secured by the house: during the draw period (often 10 years) you can borrow, repay and borrow again, and most lenders only require interest payments on what you've used.

When the draw period ends, the line closes and the repayment period begins (often 20 years). Payments then include principal, so they can jump sharply — this calculator shows both phases so the second one isn't a surprise.

How much can you borrow?

Lenders cap the combined loan-to-value (CLTV): your mortgage plus the HELOC, divided by the home's appraised value. At an 85% cap on a $450,000 home, total borrowing can reach $382,500; subtract a $250,000 mortgage and the line could be up to $132,500. Your credit score, income and debts also affect the final amount and rate.

Because your home secures the line, missing payments can lead to foreclosure. HELOCs suit planned, value-adding uses like renovations better than everyday spending.

The calculations

Maximum line = home value × CLTV − mortgage balanceInterest-only payment = balance × rate ÷ 12Repayment payment = standard loan payment over the repayment period

Example

  1. Home worth $450,000, $250,000 mortgage, 85% CLTV: maximum line ≈ $132,500.
  2. Borrow $50,000 at 8.25%: interest-only payment ≈ $343.75 a month during the draw period.
  3. Over a 20-year repayment period, the payment rises to about $426 a month.

Frequently asked questions

Is HELOC interest tax-deductible?

In the US, interest can be deductible only if the money is used to buy, build or substantially improve the home that secures the loan, and you itemize deductions. Check the current IRS rules or a tax professional.

HELOC or home equity loan?

A home equity loan gives you a lump sum at a fixed rate with fixed payments. A HELOC is a revolving line with a variable rate. A loan suits one known expense; a HELOC suits costs spread over time.

What happens if home values fall?

Lenders can freeze or reduce an unused HELOC line if your home's value drops significantly, so don't count on untapped credit as an emergency fund.

Sources

Last reviewed for 2026. How we calculate.