HELOC Calculator
Estimate the home equity line of credit you may qualify for and what the interest-only payment could be.
By Onias Derilus, Mortgage Capital · NMLS# 1859012 · Last Updated: June 2026
HELOC rates are typically variable and tied to the prime rate. During the draw period many HELOCs allow interest-only payments. Estimate only.
A home equity line of credit, or HELOC, is a revolving credit line secured by your home. Instead of a lump sum, you draw what you need during a draw period and pay interest only on the balance you use.
Your line size is limited by the combined loan-to-value — the total of your first mortgage plus the HELOC as a share of your home value. Most lenders cap that around 80% to 90%.
How to Use This Calculator
- 1
Enter your current home value.
- 2
Enter the balance on your existing first mortgage.
- 3
Set the maximum combined loan-to-value your lender allows.
- 4
Add an illustrative HELOC rate to estimate the line size and the interest-only payment if fully drawn.
The Formula & Assumptions
Max combined = value × max CLTV
Available line = max combined
− first mortgage balance
Interest-only pmt =
drawn balance × rate ÷ 12
The combined loan-to-value limit sets the ceiling on all liens against your home. We subtract your first mortgage from that ceiling to estimate the equity available for a line.
HELOC rates are usually variable and move with the prime rate, so your payment can change over time. Many HELOCs allow interest-only payments during the draw period, then require principal-plus-interest in the repayment period.
Because the line is secured by your home, missed payments put the property at risk. Borrow against equity deliberately and keep a repayment plan in mind.
Frequently Asked Questions
How is a HELOC different from a cash-out refinance?
A HELOC is a second loan that leaves your first mortgage untouched and gives you a revolving line you can draw and repay. A cash-out refinance replaces your entire mortgage with a larger one and hands you a lump sum.
What is the combined loan-to-value limit?
It is the total of all loans against your home divided by its value. If a lender caps combined LTV at 85% and you owe 55% on your first mortgage, you can borrow up to 30% of the value through the HELOC.
Are HELOC payments fixed?
Usually not. Most HELOC rates are variable and tied to the prime rate, so the payment changes as rates move. During the draw period many lines allow interest-only payments, which keeps the minimum low but does not reduce principal.
Can I get a HELOC on an investment property?
Some lenders offer them, but combined LTV limits are typically lower and rates higher than on a primary residence. Reserves and credit requirements are also stricter.
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Rates are illustrative only. APR and payments vary by credit score, loan amount, and market conditions. Subject to credit approval. Not a commitment to lend. NMLS# 1859012. Equal Housing Lender.