BYTETOOLS

HELOC Payment Calculator

Calculate a home equity line of credit: available credit from your CLTV, interest-only draw payments on a schedule of draws, and the amortising repayment phase.

Draws

Columns: description, month, amount
$132,500
Maximum credit line
$77,500
Still available
$389.58
Payment at end of draw
$477.30
Payment in repayment

Two phases

PhaseLengthRatePaymentInterest paid
Draw (interest only)10 yr8.50%$283.33 → $389.58$44,944
Repayment (amortising)20 yr8.50%$477.30$59,553
$200,000
Home equity
$55,000
Balance when repayment starts
$104,496
Total interest

Draw-period payments cover interest only, so the balance never falls until repayment begins — that is where the payment jump comes from. Most HELOC rates are variable and tied to a published index, so the fixed rates entered here are a snapshot, not a promise. Estimates only, not financial advice.

What is the HELOC Payment Calculator?

The ByteTools HELOC Payment Calculator splits a home equity line into its two very different phases.

  • Available credit from home value × CLTV limit minus the first mortgage
  • Interest-only draw payments tracked against a schedule of draws
  • Warns when your draws exceed the line the home supports
  • Amortising repayment payment from the balance at the end of the draw
  • Separate and total interest for each phase plus your home equity
  • Local, private calculation; estimates only, not advice

How to use the HELOC Payment Calculator

  1. 1

    Enter your home value, your first mortgage balance and the maximum combined LTV your lender allows.

  2. 2

    Set the draw period rate and length, and the repayment period rate and length.

  3. 3

    List your draws — a description, the month you take it and the amount — adding rows as needed.

  4. 4

    Read the maximum credit line, the credit still available and both phase payments.

  5. 5

    Check the two-phase table for interest paid in the draw and repayment periods and the total.

About the HELOC Payment Calculator

The ByteTools HELOC Payment Calculator splits a home equity line into its two very different phases. First it works out how much credit your home actually supports: the maximum combined loan-to-value your lender allows, applied to the home's value, minus what you still owe on the first mortgage.

Then it models the draw period, where you pay interest only on whatever is outstanding. Add a table of draws with the month each one is taken, and the tool tracks the balance and the interest-only payment as it climbs — the first payment and the payment at the end of the draw are usually very different numbers.

When the draw period ends, whatever is outstanding is amortised over the repayment period using the standard annuity formula, and that payment jump is shown plainly alongside total interest for each phase. HELOC rates are typically variable, so the fixed rates here are a snapshot. Everything runs in your browser with nothing uploaded. Estimates only, not financial advice.

Frequently asked questions

How much can I borrow with a HELOC?

Most lenders cap your first mortgage plus the line at 80% to 90% of the home's value. Take that percentage of the value, subtract the mortgage balance, and what remains is your line. This calculator does that with your own combined LTV limit.

How are HELOC payments calculated during the draw period?

You normally pay interest only, calculated as the outstanding balance times the annual rate divided by twelve. Because the balance rises as you draw, the payment rises with it — and none of it reduces what you owe.

What happens when the HELOC draw period ends?

The line closes to new draws and the outstanding balance converts to an amortising loan over the repayment period, typically ten to twenty years. Because you are now paying principal as well as interest, the payment can easily double or more, which is the jump this tool shows.

Is a HELOC rate fixed?

Usually not. Most HELOCs are variable and tied to a published index such as the prime rate, so your payment moves when that index moves. The rates you enter here are treated as fixed for each phase, so run a higher rate as a stress test.

What is the difference between a HELOC and a home equity loan?

A home equity loan hands you a lump sum at a fixed rate and amortises from day one. A HELOC is a revolving line you draw on as needed, usually at a variable rate, with an interest-only period first. This calculator models the HELOC structure.

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