HELOC Calculator estimates the credit line, draw period interest, and repayment period principal and interest for a home equity line of credit based on the entered rate and term.
Calculate Your HELOC Credit Limit and Monthly Payments
This HELOC calculator finds your maximum credit line. It then shows your payment in each phase. Homeowners use it to plan a home equity line of credit before they talk to a lender.
What to Enter Into the HELOC Calculator
Enter your home value, current mortgage balance, lender’s max LTV limit, planned draw amount, rate, draw period, and repayment period. The calculator treats your rate as a nominal annual percentage rate (APR), compounded monthly, not an effective annual rate. The math doesn’t depend on currency; the tool just changes the symbol shown.
The Formula Behind Your HELOC Credit Limit
Your maximum credit line is your home’s value times your lender’s max LTV, minus what you still owe:
$$\text{Max Credit} = (\text{Home Value} \times \text{Max LTV}) – \text{Mortgage Balance}$$
The 80% LTV figure here is a common lender convention, not a federal rule. CFPB consumer guidance notes many lenders cap combined borrowing around 80% of home value, though some go up to 85% or higher. This reflects common U.S. lending practice; ask your own lender for their exact limit before you rely on this number.
During the draw period, most HELOCs charge interest only on what you’ve drawn, not your full credit line:
$$\text{Draw Payment} = \text{Draw Balance} \times \frac{\text{Annual Rate}}{12}$$
This interest-only method is standard practice, described in HELOC lender education tied to CFPB borrower guidance. A common mistake: entering a monthly rate instead of the yearly APR. This calculator expects the full annual rate and divides it by 12 for you.
Once the draw period ends, your balance amortizes over the repayment term using the standard installment-loan formula:
$$\text{Repayment Payment} = \text{Draw Balance} \times \frac{r(1+r)^n}{(1+r)^n – 1}$$
Here $r$ is your monthly rate and $n$ is the number of repayment months. This is the same formula used for any fixed-rate installment loan.
One detail a basic calculator often misses: the jump between your draw-period payment and your repayment-period payment can be large, even if your rate never changes. If you only pay interest through the whole draw period, your repayment payment must cover 100% of the principal in a shorter window. The CFPB calls this jump payment shock, and names it a leading cause of financial strain for HELOC borrowers.
Valid inputs stay in normal ranges: LTV between 1% and 100%, rate at 0% or higher, and terms of at least one year. At a 0% rate, your draw payment drops to $0, and your repayment payment becomes an even split of the balance across the term. If your mortgage balance exceeds your max LTV limit, available credit shows as $0, not a negative number, since a HELOC can’t create negative credit.
This calculator gives estimates based on what you enter. It isn’t personalized loan, tax, or financial advice. Your actual rate, limit, and payment depend on your lender’s underwriting.
Draw Phase vs. Repayment Phase Payment Jump
Current Average HELOC and Home Equity Loan Rates
As of July 29, 2026, Bankrate’s survey of major home equity lenders puts the national average HELOC rate at 7.44% and the average fixed home equity loan rate at 8.10%. These are U.S. national figures. They move with each Federal Reserve rate decision, so check today’s number before using this calculator’s default rate for real planning.
Common Questions About HELOC Credit Limits and Payments
What’s the difference between my HELOC limit and my draw amount?
Your HELOC limit is the total credit line your lender approves. Your draw amount is what you actually borrow against that line. You only owe interest on what you draw.
Why does my payment jump after the draw period?
During the draw period, most HELOCs only require interest payments. Once repayment starts, you must pay off the full principal too, over a shorter fixed term. That’s the jump.
Can I pay down principal during the draw period?
Yes. Most lenders let you pay more than the interest-only minimum during the draw period. Extra payments now lower your balance and your repayment-period payment later.
What happens to my HELOC if my home value drops?
A lower home value raises your LTV ratio. If it passes your lender’s limit, they can freeze or reduce your available credit, even mid-draw period.
Is my HELOC rate fixed or variable?
Most HELOCs carry a variable rate tied to the prime rate, so your payment can change over time. Some lenders let you lock part of the balance to a fixed rate.
Does a bigger draw always mean a bigger HELOC payment?
Yes. A larger draw raises both your interest-only payment and your later amortizing payment, since both scale directly with the balance you borrow.