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Mortgage Calculators

HELOC Payment Calculator

Estimate HELOC payments during the interest-only draw period and the amortized repayment period.

Standard HELOC structure: interest-only during draw, then fully amortized over the repayment period.

$
%
yr
yr
Interest-only draw payment
$354/mo
Jumps to $434/mo when repayment begins.
Draw phase monthly
$354
Repayment phase monthly
$434
Interest during draw
$42,500
Interest during repayment
$54,139
Total interest (both phases)
$96,639
Overview

How the HELOC Payment Calculator Works

A HELOC has two phases most borrowers don't fully understand until they get hit with the second one. During the draw period you typically pay interest only; when repayment begins, the balance amortizes over the remaining term and payments can double or triple. This calculator shows both phases side by side.

Formula

The Math Behind the Calculator

Draw monthly = Balance × (APR / 12). Repayment monthly = Balance × r / (1 − (1+r)^−n), where r = APR/12 and n = repayment months.

Example

A Worked Example

On a $50,000 HELOC at 8.5% APR with a 10-year draw and 20-year repayment: interest-only payment during draw is about $354/month. Once repayment begins, the amortized payment jumps to about $434/month — modest here, but on larger balances the jump is dramatic.

How to use

How to Use the HELOC Payment Calculator

  1. 1Enter the HELOC balance you'll actually carry.
  2. 2Enter the current APR — HELOCs are typically variable, so use today's rate as a baseline.
  3. 3Enter the draw period (often 10 years) and the repayment period (often 15 or 20 years).
Interpretation

What the Results Mean

  • Draw monthly is what you'll pay while the line is open — deceptively low.
  • Repayment monthly is what hits when draw ends — the real cost picture.
  • Total interest across both phases is the true price of the borrowed money.
Avoid

Common Mistakes to Avoid

  • Only budgeting for the interest-only phase and being blindsided by the repayment jump.
  • Ignoring the variable rate — HELOC rates typically follow the prime rate and can rise significantly.
  • Using a HELOC for depreciating purchases (cars, vacations) instead of home improvements or emergencies.
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FAQ

Frequently Asked Questions

Are HELOC rates fixed or variable?+

Almost always variable, tied to prime. This calculator uses one rate for illustration — reality will fluctuate.

Can I pay off a HELOC early?+

Yes, usually without penalty. Extra payments go to principal and reduce future interest.

What's the risk?+

The HELOC is secured by your home. Missing payments can lead to foreclosure, just like a first mortgage.

Financial Disclaimer

This calculator is for educational and estimation purposes only. It does not provide financial, mortgage, tax, investment, or legal advice. Actual rates, payments, taxes, fees, insurance costs, eligibility, and loan terms vary by lender, location, credit profile, and market conditions. Always compare official offers and consult a qualified professional before making financial decisions.

Last updated June 2026 · Prepared by the mCalculator Editorial Team