HELOC Calculator
Calculate your Home Equity Line of Credit limit, draw-period interest-only payments, and repayment-period P&I payments. See CLTV, max credit line, and total interest across both phases.
Calculation Inputs
HELOCs use variable rates, typically Prime + margin. Current Prime ~8.5%.
Estimated average amount you plan to draw each month.
Results computed instantly — your data never leaves your device.
Live Results
Real-TimeApproved Credit Line
$60,000
Current Home Equity
$170,000
Draw Period Monthly Interest
$218.75
Interest-only on avg drawn balance
Repayment Monthly Payment
$530.23
P&I over 20 years
CLTV After HELOC
75.6%
Total Interest (est.)
$93,504.34
HELOC Phases
10 yrs · interest-only
20 yrs · P&I
How to Use the HELOC Calculator
- 1
Enter your current home value and remaining mortgage balance to determine available equity.
- 2
Input your desired credit limit — the calculator will cap it at the lender's maximum CLTV (typically 85%).
- 3
Set the interest rate (check current Prime rate + your lender's margin), draw period, and repayment period.
- 4
Enter your estimated average monthly draw to project total interest costs across both phases.
- 5
Review the CLTV ratio, draw-period interest-only payment, and repayment-period P&I payment.
Formula & Mathematical Basis
Variable Key
CLTVCombined Loan-to-Value ratio — total debt secured by the property divided by appraised value
Draw InterestOutstanding Balance × (Annual Rate ÷ 12) — interest-only during draw period
Repayment PMTStandard amortization formula applied to balance outstanding at end of draw period
📝 Interest during the draw period accrues only on amounts actually drawn, not the full credit limit. This calculator uses an average draw model for projection; actual costs depend on your draw pattern.
Step-by-Step Examples
Home renovation HELOC
Scenario: $500,000 home, $300,000 mortgage, 85% CLTV, 8.75% rate, 10-year draw, $500/mo draw.
- 1.Max HELOC = $500,000 × 0.85 − $300,000 = $125,000.
- 2.CLTV after HELOC = ($300,000 + $125,000) / $500,000 = 85%.
- 3.Draw-period interest on avg balance ($31,250): $31,250 × 8.75%/12 ≈ $228/month.
- 4.Repayment: $125,000 over 20 years at 8.75% ≈ $1,107/month.
Practical Use Cases
- Home renovation and remodeling — kitchen, bathroom, or addition financing
- Emergency fund backstop — low-cost standby credit without drawing unless needed
- Debt consolidation — paying off high-interest credit cards with home equity at lower rates
- Education expenses — tuition and college costs financed over time
- Investment property down payment — using equity in primary residence
Common Pitfalls
- Treating a HELOC as permanent income — the lender can reduce or freeze the line if your home value drops or creditworthiness changes.
- Interest-only mindset — paying only the draw-period minimum means the full balance remains and payment shock arrives at repayment.
- Variable rate risk — a 2% rate increase on a $100,000 balance adds $167/month to your payment.
- Over-leveraging — borrowing to the CLTV maximum leaves no equity buffer if home prices decline.
Frequently Asked Questions
What is the difference between a HELOC and a home equity loan?
A HELOC is a revolving credit line — you borrow, repay, and re-borrow during the draw period, paying interest only on the outstanding balance. A home equity loan disburses a lump sum upfront with fixed monthly P&I payments from day one.
How is a HELOC credit limit determined?
Lenders calculate the maximum Combined Loan-to-Value (CLTV) — typically 80–90% of your home's appraised value — and subtract your existing mortgage balance. For example: $500,000 home × 85% CLTV − $300,000 mortgage = $125,000 maximum HELOC.
Are HELOC interest rates fixed or variable?
Most HELOCs have variable rates tied to the Prime Rate plus a margin (e.g. Prime + 0.5%). This means your payment changes when the Fed adjusts rates. Some lenders offer rate-lock options to convert a portion to a fixed rate.
Can I deduct HELOC interest on my taxes?
As of the Tax Cuts and Jobs Act (2018), HELOC interest is only deductible if the funds are used to "buy, build, or substantially improve" the home securing the loan. Using HELOC funds for other purposes (debt consolidation, vacations) disqualifies the deduction.
What happens at the end of the draw period?
The HELOC enters repayment. You can no longer draw funds and must repay the outstanding balance — usually as fully amortizing P&I payments. Some HELOCs require a balloon payment; confirm the terms with your lender.
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