Calcs4All

APR 23 · 2026

HELOC payment calculator

Compare simplified interest-only and amortizing repayment payments for a HELOC-style balance.

What this calculator covers

Estimate how a HELOC balance can feel during an interest-only period versus a repayment period.

The walkthrough is intentionally simplified so the payment jump risk stays visible without pretending to replace a lender statement or variable-rate disclosure.

Frequently asked questions

What is the difference between a HELOC draw period and a repayment period?
During the draw period you can borrow against the line and typically make interest-only payments. Once the draw period ends, the repayment period begins and you must pay back the principal — often over a shorter window, which raises the monthly payment significantly.
Why does the repayment payment look so much higher than the interest-only payment?
The interest-only phase covers only the cost of carrying the balance. The repayment phase must return the full principal plus interest over a fixed term, so the same balance produces a larger monthly obligation once amortization starts.
Are HELOC rates fixed or variable?
Most HELOCs carry variable rates tied to a benchmark such as the prime rate, so your actual payment can change month to month. This calculator uses a single rate as a planning snapshot and does not model rate adjustments.
Does this estimate include fees or closing costs?
No. Lenders may charge origination fees, annual fees, or closing costs that are not reflected here. Contact your lender for a full cost disclosure before drawing on a home equity line.

Tool

Run the calculation

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RESULT · HELOC PAYMENT

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Primary result

$837.03

On a $85,000.00 HELOC balance at 8.5%, the interest-only payment is about $602.08 per month, while a 15-year amortizing repayment would be about $837.03 per month.

Interest-only payment
$602.08
Amortizing payment
$837.03
Total repayment cost
$150,665.15

Step-by-step solution

  1. 1.Estimate the draw-period interest-only payment from the current balance and annual rate to get $602.08 per month.
  2. 2.Amortize the same balance over 15 years to estimate a repayment-phase payment of $837.03 per month.
  3. 3.Multiply the amortizing payment across the repayment term to estimate $150,665.15 in total repayment if the rate stayed constant.

Walkthrough

Visual walkthrough

A HELOC can feel inexpensive during an interest-only draw period, then jump materially when repayment begins and principal must be repaid.

  1. 01

    Estimate the draw-period minimum

    $85,000.00 × 8.5% ÷ 12 = $602.08

    Interest-only payments depend on the current balance and the current rate.

    $602.08 interest-only

  2. 02

    Switch to repayment math

    Once the draw period ends, the same balance often has to amortize over a shorter repayment window.

    $837.03 amortizing payment

  3. 03

    Read the payment jump

    Comparing the two monthly figures helps show the payment shock risk many borrowers face at repayment conversion.

    $234.95 higher than interest-only