HELOC Calculator
Size a home equity line of credit against your available equity, then price both the interest-only draw period and the payment shock when repayment begins.
HELOC Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Results are a model, not a quotation — an institution's own figures govern.
- Every input is an assumption; change one and the answer changes with it.
- Rounding is applied only at the display layer, so totals may differ by a cent from a statement that rounds each line.
In short: A HELOC lets you borrow against equity up to a combined loan-to-value limit, usually 85%. On a $420,000 home with a $260,000 first mortgage that is a $97,000 line. Drawing $75,000 at 8.5% costs $531.25 monthly interest-only, rising to $650.87 once repayment starts.
Formula
During the draw period only interest is due, so the balance never falls. Repayment amortises whatever remains over the repayment term.
Worked Example
- Find the ceiling. 85% of $420,000 = $357,000.00 of total permitted debt.
- Deduct the first mortgage. $357,000.00 − $260,000 = $97,000.00 of available line.
- Price the draw. $75,000 at 8.5% costs $531.25 monthly, interest only.
- Price the reset. Amortising $75,000 over 20 years gives $650.87.
- Measure the shock. A $119.62 increase — and the rate is variable, so it can be far larger.
Analyst note. Two risks compound here. The payment rises when the draw period ends, and the rate itself is variable, typically prime plus a margin. A two-point rise takes the interest-only payment from $531.25 to $656.25 before any amortisation begins. Ten years of interest-only payments also means the $75,000 balance is entirely undiminished at reset.
Strengths & Limits Of This Model
Where this engine is strong
- Runs entirely in your browser — no figure you type is transmitted or stored.
- Shows the full working, so every number can be traced and challenged.
- Free, unmetered and free of affiliate incentives.
Where it stops
- Generalised assumptions cannot capture every individual circumstance.
- Jurisdiction-specific rules and mid-year changes may not be reflected.
- A model output is not a substitute for a professional review of your position.
Practical Use Cases
Funding a renovation in stages
A line charges interest only on what you actually draw, which suits phased work far better than a lump sum. Compare against a fixed alternative with the Home Equity Loan Calculator.
Maintaining a standby emergency facility
An undrawn line costs nothing but annual fees and provides liquidity secured at mortgage-like rates. The risk is that lenders can freeze or reduce lines when values fall.
Consolidating higher-rate debt
Replacing credit card debt at 20% with secured borrowing at 8.5% is arithmetically attractive but converts unsecured debt into debt against your home. Check the ratio impact with the Debt To Income Calculator.
Methodology & Editorial Standards
The available line is the property value multiplied by the maximum combined loan-to-value ratio, less the outstanding first mortgage balance. Eighty-five percent is the common ceiling, though some lenders extend to 90% at higher rates and stronger credit. During the draw period the payment is pure interest on the drawn balance, so no principal is retired. At reset the remaining balance is amortised over the repayment term, producing the payment shock shown. The model holds the rate constant for clarity, but HELOC rates are variable and tied to an index plus margin, so both the draw and repayment figures move with the index. Draws are assumed taken at the outset rather than staged. The engine implements the standard published formula for this calculation. Inputs are validated for domain and sign before evaluation, and any undefined case returns an em-dash rather than a spurious value.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
HELOC Calculator — 20 Expert FAQs
20 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How much can I borrow with a HELOC?
Usually up to 85% of your home's value less the first mortgage. On a $420,000 home with $260,000 outstanding, that is a $97,000 line. Some lenders go to 90%, and a few to 100% at much higher rates.
What is CLTV?
Combined loan-to-value: all mortgage debt divided by the property value. Drawing $75,000 on top of a $260,000 first mortgage takes CLTV to 79.76%, still inside the 85% ceiling.
What happens when the draw period ends?
The line closes to new borrowing and the balance amortises. Here the payment rises from $531.25 to $650.87. Because interest-only payments retire no principal, the full $75,000 is still outstanding at reset.
Are HELOC rates fixed or variable?
Almost always variable, typically prime plus a margin, adjusting monthly. A two-point rise takes this payment from $531.25 to $656.25. Some lenders permit converting a portion to a fixed rate.
Is a HELOC better than a home equity loan?
A HELOC suits uncertain, staged spending because you pay interest only on what you draw. A home equity loan suits a known lump sum, since the rate is fixed and the payment never changes.
Can a lender freeze my HELOC?
Yes. Lenders may reduce or suspend lines if property values fall materially or your financial position deteriorates. This happened widely in 2008 and is the principal weakness of relying on a line for emergencies.
Is HELOC interest tax deductible?
Only when the proceeds are used to buy, build or substantially improve the property securing the loan, and subject to overall debt limits. Using it for other purposes generally makes interest non-deductible.
What are typical HELOC fees?
Often minimal to open, sometimes with no closing costs, but expect annual fees and occasionally early closure fees if you repay within the first few years. Appraisal costs may also apply.
Can I pay off a HELOC early?
Yes, and during the draw period you can repay and redraw freely, which is the flexibility that distinguishes it from a loan. Check for early closure fees in the first two or three years.
Does a HELOC affect my credit score?
Yes. It appears as revolving credit, so high utilisation of the line can weigh on your score much as a maxed credit card would, even though it is secured against property.
What credit score do I need?
Typically 680 or higher for competitive terms, though some lenders accept 620 with lower CLTV limits. Both rate and maximum CLTV tighten as the score falls.
Should I use a HELOC to consolidate credit cards?
The rate arbitrage is compelling, from around 20% to 8.5%, but it converts unsecured debt into debt secured on your home. Missing payments on a card damages credit; missing them here risks the property.
Is this heloc calculator free to use?
Yes. It is free, requires no account, and has no usage limits. ApexConverter is funded by contextual advertising, never by selling user data.
Is my data sent to a server?
No. The engine runs as Vanilla JavaScript inside your browser under our Zero-Server Client-Side Execution model. Your figures are computed locally and are never transmitted, logged, or stored.
How accurate is this calculator?
It applies the standard closed-form formula in IEEE-754 double precision, rounding only at the display layer. The engine is reconciled against an independent reference implementation before release.
Does it work on mobile?
Yes. The interface is mobile-first with numeric keypad hints and is tested down to a 320-pixel viewport with no horizontal scrolling.
Can I use it offline?
Largely, yes. Because computation is client-side, the page continues to calculate without a network connection once it has loaded.
Which currency does it use?
Amounts display in US$ accounting format, but the underlying mathematics is currency-agnostic. The result is identical in any currency, so simply read the figures in your own.
Why does a result show an em-dash?
An em-dash indicates the calculation is not defined for the inputs given — typically a division by zero or a value outside the valid domain. We show a dash rather than a misleading number.
How do I report an error?
Email apexconverter.praxiscalc@gmail.com with the tool URL, your exact inputs, the output received and the output you expected. Verified mathematical errors are patched within 72 hours.