How much can you borrow with a home equity line of credit, and what will it cost? This HELOC calculator estimates your maximum credit line, your interest-only payment during the draw period, the higher payment once repayment starts, and how much more you’d pay if rates rise.
You could borrow up to
—
Your monthly payment over time
Assumes you borrow the full amount at the start and the rate stays the same.
If your rate goes up
| Rate | Draw period payment | Repayment payment | Total interest |
|---|
Most HELOCs have variable rates tied to the prime rate, so your payment can change.
Estimates only. Your credit limit, rate, fees and terms depend on your lender, credit profile and an appraisal of your home.
How much can you borrow with a HELOC?
Lenders limit the total of all loans on your home to a percentage of its value, called the combined loan-to-value ratio (CLTV). Many cap it at 80% to 85%, and many look for you to keep at least 15% equity. Your maximum credit line is:
Maximum HELOC = (home value × maximum CLTV) − mortgage balance
Example: with a $500,000 home and a $300,000 mortgage, an 85% limit allows $425,000 in total loans, so you could borrow up to $125,000. At an 80% limit the line drops to $100,000; at 90% it rises to $150,000. The final amount depends on an appraisal, your credit score and your income.
How HELOC payments work
A HELOC has two phases:
- Draw period (typically 3 to 10 years): you can borrow, repay and borrow again up to your limit. Payments are often interest only.
- Repayment period (typically 10 to 20 years or more): you can no longer borrow, and you repay principal and interest until the balance is zero.
Borrowing $50,000 at 7.5% with a 10-year draw period and 20-year repayment period, the interest-only payment is $312.50 a month. When repayment starts, it rises to $402.80, a jump of $90.30 a month. Over the full 30 years you’d pay about $84,171 in interest.
That jump is called payment shock, and it grows with the amount you borrow. On $100,000, the payment goes from $625.00 to $805.59. A shorter repayment period makes it bigger too: with 15 years to repay the same $50,000, the payment rises to $463.51.
Interest-only vs. paying principal from the start
Interest-only payments keep costs low early on, but your balance doesn’t shrink. If you pay principal and interest from day one, the payment on $50,000 is $349.61 for the whole 30 years, with no jump, and total interest falls to about $75,859. Switch the “Payments during the draw period” option in the calculator to compare.
HELOC rates are usually variable
Most HELOCs have a variable rate equal to the prime rate plus a margin set by your lender. The prime rate was 7.00% in early October 2026, and average HELOC rates were around 7%, though rates vary widely with credit score and lender. When prime rises, so does your payment.
The table in the calculator shows what happens if your rate climbs. On the $50,000 example, a 2-point increase to 9.5% raises the draw-period payment to $395.83 and the repayment payment to $466.07, adding about $25,000 in interest. Some lenders let you lock part of your balance at a fixed rate; ask about it if rising rates worry you.
HELOC vs. home equity loan vs. cash-out refinance
| Option | How you get the money | Rate | Best for |
|---|---|---|---|
| HELOC | Revolving line; borrow as needed | Usually variable | Ongoing or uncertain costs, like a renovation done in stages |
| Home equity loan | Lump sum | Usually fixed | One known expense with a predictable payment |
| Cash-out refinance | Replaces your mortgage with a bigger one | Fixed or adjustable | When today’s mortgage rates are at or below your current rate |
If your current mortgage rate is low, a HELOC lets you tap equity without giving it up. To compare a cash-out refinance, use our refinance calculator, and see our picks for the best HELOC lenders.
Risks to understand before you borrow
- Your home is the collateral. If you can’t make the payments, you could lose your home.
- Payments can rise when the draw period ends and when rates go up.
- Lenders can freeze or reduce your line if your home’s value drops significantly or your finances change.
- Fees: some HELOCs charge appraisal, annual or early-closure fees. Compare total costs, not just the rate.
- Taxes: HELOC interest may be tax-deductible only if you use the money to buy, build or substantially improve the home that secures the loan. Check with a tax professional.
Using a HELOC to pay off high-interest credit cards can lower your interest cost, but it turns unsecured debt into debt secured by your home. Lenders also look at your credit, so check your credit report before you apply. To see your full first-mortgage payment, use our mortgage calculator.
Frequently asked questions
How much can I borrow with a HELOC?
Multiply your home’s value by the lender’s maximum combined loan-to-value ratio, often 80% to 85%, then subtract your mortgage balance. With a $500,000 home, a $300,000 mortgage and an 85% limit, you could borrow up to $125,000.
What is the monthly payment on a $50,000 HELOC?
At 7.5%, the interest-only payment during the draw period is $312.50 a month. If the remaining balance is repaid over 20 years, the payment rises to about $402.80 a month once repayment begins.
How is HELOC interest calculated?
Interest is charged only on the amount you’ve borrowed, not your full credit line. The monthly interest equals your balance times the annual rate divided by 12. Because most HELOC rates are variable, the amount changes when the prime rate moves.
What happens when the HELOC draw period ends?
You can no longer borrow, and your payments switch to principal and interest so the balance is paid off over the repayment period. This usually means a higher monthly payment than during an interest-only draw period.
Is a HELOC better than a cash-out refinance?
A HELOC is often better if your current mortgage rate is lower than today’s rates, because you keep that rate and only pay interest on what you borrow. A cash-out refinance can make sense when you can also lower your mortgage rate or want one fixed payment.
This calculator provides estimates for educational purposes only and is not financial or tax advice. Sources: Lower: How Does a HELOC Work?; LendEDU: current HELOC rates and prime rate (October 2026).