What is the difference between the draw period and the repayment period?

During the draw period (usually 10 years) you can borrow against the line and typically pay interest only, so your payment is low. When the draw period ends, the repayment period begins (often 20 years) and your payment switches to principal plus interest, fully paying the balance to zero. Because principal is now included, the payment jumps — that jump is the payment shock this tool highlights.

What CLTV do HELOC lenders allow?

80%–85% combined loan-to-value is the most common standard. 90% generally requires strong credit (FICO around 740+), and a few lenders go higher. The default of 85% is a reasonable middle estimate, not a guarantee — your actual limit depends on the lender's appraisal, your credit, and your debt-to-income ratio.

Is this HELOC calculator free?

Yes — 100% free. Everything is calculated privately in your browser; nothing is stored or sold. It's an educational estimate, not a loan offer or quote.

HELOC Payment Calculator

Q: How much can I borrow with a HELOC?

Your borrowing limit is set by your lender's maximum combined loan-to-value (CLTV). Take your home value times the max CLTV, then subtract every existing mortgage and lien. For example, a $500,000 home at 85% CLTV gives an $425,000 ceiling; subtract a $300,000 mortgage balance and you can borrow up to about $125,000. This calculator does that math and rounds the limit down to be conservative.

Q: Why does my HELOC payment jump after the draw period?

Interest-only draw payments only cover the interest, leaving the full balance outstanding. When repayment begins, that whole balance must amortize over the repayment term, so principal is added on top of interest. On a $50,000 balance at 8%, the interest-only draw payment is about $333/mo but the repayment payment over 20 years is about $418/mo — a roughly $85, or 25%, increase.

Q: Are HELOC rates fixed?

No. HELOCs are almost always variable-rate, set as the Prime rate plus a margin, and the rate can change monthly during both the draw and repayment periods. Prime was about 7.50% in mid-2026, putting typical HELOC APRs around 7.25%–8.50%. This calculator's repayment figure assumes the rate at calculation time stays constant; use the stress-rate field to model a higher future rate.

How much you can borrow & the payment shock when repayment begins

Home value (appraised)

Current market / appraised value — lenders lend against this, not what you paid.

Mortgage balance owed

All existing liens (1st + 2nd) — the current balance, not the original loan amount.

Max CLTV the lender allows %

80–85% is standard; 90% needs strong credit.

Amount you want to borrow

Your HELOC draw balance — capped to the limit above.

Interest rate (APR) %

HELOCs are variable (Prime + margin). Mid-2026 Prime ≈ 7.50%.

Draw period (years)

Interest-only window. Standard is 10 years.

Repayment period (years)

Principal + interest amortizes to zero. Standard is 20 years.

Stress / rate-shock rate % (optional)

Worst-case future rate to stress-test the repayment payment.

Maximum you can likely borrow

CLTV limit

Draw period

interest-only

Repayment period

principal + interest

Educational estimate, not a loan offer or quote. HELOC rates are variable (Prime + margin) and can change monthly — the repayment figure assumes today's rate stays constant. Figures assume the full balance is drawn and held interest-only through the draw period, then fully amortizes over the repayment term. Excludes closing costs, annual/inactivity fees, taxes and insurance. Actual limits and rates depend on the lender's appraisal, your credit, and debt-to-income ratio.

HELOC Payment Calculator — guide & how to use

What it does

A HELOC (home equity line of credit) has two phases, and the payment is very different in each. During the draw period (usually 10 years) you can borrow against the line and typically pay interest only, so the payment is low. When the draw period ends, the repayment period (often 20 years) begins and the payment switches to principal plus interest so the balance is paid down to zero — which makes the payment jump. This calculator shows three things: how much you can likely borrow (from your home value and your lender's CLTV cap), your interest-only draw payment vs your amortized repayment payment, and the payment shock — the dollar and percent jump — plus an optional rate-shock scenario. Everything runs privately in your browser, free.

How to use it

Enter your home value (current market or appraised) and your current mortgage balance across all liens.
Set the max CLTV your lender allows (80–85% is typical) — this drives your borrowing limit.
Enter the amount you want to borrow; it's capped to your calculated limit, and the tool warns you if you ask for more.
Set the APR, draw period, and repayment period, then read your draw vs repayment payments and the shock.
Optionally set a higher stress rate to see the worst-case repayment payment if the variable rate rises.

The formulas

Borrowing limit: max HELOC = (home value × max CLTV) − current mortgage balance, clamped to ≥ $0 and rounded down to the nearest $100.
Interest-only draw payment: balance × (APR ÷ 12).
Amortized repayment payment: balance × [ i(1+i)ⁿ ] ÷ [ (1+i)ⁿ − 1 ], where i = monthly rate and n = repayment months. If the rate is 0%, it's simply balance ÷ n.
Payment shock: repayment payment − draw payment, in dollars and percent.

Worked example

A $500,000 home with a $300,000 mortgage balance, an 85% CLTV cap, borrowing $50,000 at an 8% APR with a 10-year draw and a 20-year repayment:

Limit  = ($500,000 × 0.85) − $300,000 = $125,000 available
Draw   = $50,000 × (0.08 ÷ 12)        = $333.33 / mo (interest-only)
Repay  = $50,000 amortized over 240 mo at 8% = $418.22 / mo (P&I)
Shock  = $418.22 − $333.33 = +$84.89 / mo  (+25.5%)

So you could borrow up to $125,000, your interest-only payment on a $50,000 draw is about $333/mo, and it rises to about $418/mo — a roughly $85, or 25%, jump — once repayment begins.

Common mistakes this tool helps you avoid

Using the original mortgage amount instead of the current remaining balance — that overstates your equity.
Forgetting second liens — CLTV is the combined loan-to-value across all mortgages.
Treating the cheap interest-only draw payment as the "real" payment and being blindsided by the repayment jump.
Amortizing over the total 30-year term instead of just the repayment term — principal only amortizes during repayment.
Assuming the variable rate stays fixed — always treat the repayment figure as "at today's rate," and use the stress field.

Accuracy & assumptions

This is an educational estimate, not a loan offer or quote. Actual borrowing limits and rates depend on a lender's appraisal, your credit score, and your debt-to-income ratio. HELOC rates are variable (typically Prime + a margin; Prime was about 7.50% in mid-2026) and can change monthly during both the draw and repayment periods — your real payment will move with the rate. The interest-only draw payment assumes you've drawn the full balance and carry it the whole draw period; if you draw less or pay down principal during the draw, your payment and eventual balance will be lower. The repayment payment assumes the full balance amortizes over the repayment term with no further draws. Total-interest figures are rough lifetime estimates under a constant-rate, fully-drawn assumption. This tool excludes closing costs, annual/inactivity fees, early-closure fees, and property taxes/insurance. Carry full precision through the math; only displayed dollars are rounded, and the limit is rounded down to be conservative.

How to embed this tool on your website

No account, no coding. Copy the embed code and paste it where you want it to appear:

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  title="HELOC Payment Calculator" loading="lazy"></iframe>
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Frequently asked questions

How much can I borrow with a HELOC?

Your limit is set by your lender's max combined loan-to-value (CLTV): home value × max CLTV, minus every existing mortgage and lien. A $500,000 home at 85% gives a $425,000 ceiling; subtract a $300,000 balance and you can borrow up to about $125,000. This tool rounds the limit down to be conservative.

What is the difference between the draw and repayment periods?

The draw period (usually 10 years) is when you can borrow and typically pay interest only, so the payment is low. The repayment period (often 20 years) switches to principal + interest to pay the balance to zero — which is why the payment jumps.

Why does my HELOC payment jump after the draw period?

Interest-only payments leave the full balance outstanding. When repayment begins, that whole balance amortizes over the repayment term, adding principal on top of interest. On a $50,000 balance at 8%, the draw payment is about $333/mo but the repayment payment is about $418/mo — roughly +$85, or +25%.

Are HELOC rates fixed?

No — they're variable (Prime + a margin) and can change monthly during both phases. Prime was about 7.50% in mid-2026, so typical HELOC APRs ran ~7.25%–8.50%. The repayment figure here assumes today's rate stays constant; use the stress field to model a higher rate.

What CLTV do lenders allow?

80%–85% is most common; 90% usually needs strong credit (FICO ~740+), and a few lenders go higher. The default 85% is a reasonable middle estimate, not a guarantee.

Is it really free?

Yes — 100% free, and everything runs in your browser. It's an educational estimate, not a loan offer.

Related tools

Embed this calculator on your site

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<iframe src="https://snaptoolsuite.com/heloc-payment-calculator/?embed=1"
  style="width:100%;max-width:560px;height:980px;border:0;"
  title="HELOC Payment Calculator" loading="lazy"></iframe>
<p>Free <a href="https://snaptoolsuite.com/heloc-payment-calculator/">HELOC Payment Calculator</a> by Snap Tool Suite</p>

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3 It just works

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