HELOC Calculator

What is a HELOC calculator?

A home equity line of credit, or HELOC, lets you borrow against your home's equity the way a credit card lets you borrow against a credit limit. A lender approves a maximum amount, and you draw from it as needed instead of taking one lump sum. This calculator estimates your available credit from your home value and mortgage balance, then models the two phases every HELOC goes through: an interest-only draw period, and a fully amortizing repayment period once it ends.

How to use this HELOC calculator

1. Home value, your home's current market value.
2. Existing mortgage balance, what you still owe on your first mortgage.
3. CLTV limit, the maximum combined loan-to-value a lender allows, commonly 80 to 85 percent.
4. HELOC interest rate, the annual rate you expect to pay. Real rates are variable, see the note below.
5. Amount you plan to draw, how much of your available credit you actually intend to use, can be less than your full line.
6. Draw period, how many years you can draw funds, typically 5 to 10.
7. Repayment period, how many years you have to pay off the drawn balance afterward, typically 10 to 20.

Results update instantly as you type, showing your available credit, both monthly payments, the size of the jump between them, and total interest across the life of the line.

How the draw and repayment periods work

A HELOC is a two-phase product, and mixing up the phases is the most common way borrowers get caught off guard. During the draw period, you can borrow, repay and borrow again up to your limit, and many lenders only require interest-only payments on the drawn balance, not the full available credit. That keeps payments low but does not reduce the balance. Once the draw period ends, the line moves into the repayment period: no more draws, and the remaining balance amortizes, so each payment covers both principal and interest until it reaches zero.

That jump between payments is real and can be large, often called payment shock. A borrower paying interest only on a $50,000 draw might owe a few hundred dollars a month, then see that payment roughly double once repayment starts and principal is added in. This calculator puts both numbers side by side so you can plan ahead.

HELOC vs. home equity loan vs. cash-out refinance

All three turn home equity into cash, but they work differently. A home equity loan gives you a lump sum upfront at a fixed rate, like a second mortgage. A cash-out refinance replaces your entire first mortgage with a new, larger one and hands you the difference in cash, resetting your rate and term. AHELOC is a revolving line, you draw only what you need, when you need it, usually at a variable rate. That flexibility suits ongoing or uncertain expenses, like a phased renovation, better than a single lump-sum loan or refinance.

A note on variable rates

Real HELOC rates are variable, tied to an index such as the prime rate, and can move up or down through the draw and repayment periods. This calculator uses the single fixed rate you enter for the whole timeline, a simplification worth stating plainly. Treat the results as an estimate for that rate, not a guarantee of what you will actually pay.

Frequently asked questions

This tool is for general information only and is not financial or lending advice. Confirm your actual available credit, rate and terms with your lender.

Related: Loan & Mortgage Calculator, Mortgage Refinance Calculator, Down Payment Calculator.