HELOC Calculator: Credit Line and Payment

See how much home equity you could borrow and what your HELOC payment looks like before and after the draw period ends.

HELOC calculator

Home value$Mortgage balance$Max combined loan-to-value%Amount you want to borrow$HELOC interest rate%Draw periodyrsRepayment periodyrs

Estimates for learning only — not a loan offer. Real numbers come from a lender’s Loan Estimate.

How much can you borrow with a HELOC?

A home equity line of credit (HELOC) lets you borrow against the part of your home you own outright. Lenders usually cap your combined loan-to-value (CLTV), which means your mortgage plus the HELOC, at around 80% to 85% of the home’s value, sometimes higher at certain lenders.

The formula is simple: home value × max CLTV − mortgage balance = possible credit line. Your credit score, income and debts decide whether you get the full amount.

ExampleA $450,000 home with a $250,000 mortgage and an 85% CLTV limit leaves room for about $132,500. Borrow $50,000 at 8.5%, and the interest-only payment during the draw period is about $354 a month. When repayment starts, it jumps to about $434 a month over 20 years.

Draw period vs repayment period

	Draw period	Repayment period
Typical length	Often 10 years	Often 10–20 years
Can you borrow?	Yes, as needed	No
Payment	Often interest-only	Principal + interest

That switch is the “payment shock” many people miss. The calculator shows the jump so you can plan for it.

Myth buster“My HELOC rate is locked in.” Most HELOC rates are variable and tied to the prime rate, so your payment moves when the Federal Reserve raises or cuts rates. Some lenders let you lock part of the balance at a fixed rate.

HELOC or home equity loan?

A HELOC works like a credit card backed by your house: borrow, repay, borrow again. A home equity loan gives you a lump sum at a fixed rate. Our HELOC vs home equity loan guide compares them, and a cash-out refinance is a third option if your current mortgage rate is high anyway.

Remember: your home secures a HELOC. If you can’t repay, you could lose the house. Borrow for things that add value, like repairs, rather than everyday spending.

FAQ

How much equity do I need for a HELOC?

Many lenders want you to keep at least 15% to 20% equity after the HELOC, which is why CLTV limits of 80%–85% are common.

Are HELOC payments interest-only?

Often during the draw period, yes. After that, you repay principal and interest, so the payment rises.

Is HELOC interest tax deductible?

It can be, if the money is used to buy, build or substantially improve the home that secures it, under IRS rules. Check IRS Publication 936 or a tax professional.

Does a HELOC affect my credit score?

Applying causes a hard inquiry, and a high balance can raise your credit utilization. Paying on time helps your score over time.

Sources: CFPB guide to home equity lines of credit; IRS Publication 936. Assumes the rate stays the same; real HELOC rates usually vary. Estimates for education only. Keys & Coffee is not a lender.