HELOC Calculator: How Much Home Equity Can You Borrow?

You can't just look at your home's value and subtract your mortgage balance to know what you can borrow. Lenders never let you access 100% of your equity — and the formula they use consistently surprises homeowners who expected a much bigger line of credit.

Here's the calculation you actually need, along with the number that matters most: your Combined Loan-to-Value ratio.

The Formula Lenders Use

Most lenders cap your total borrowing at 80% to 85% of your home's appraised value. That cap includes your existing mortgage — it's not 80% on top of it.

The accessible equity formula:

(Home appraised value × lender's CLTV limit) − existing mortgage balance = maximum HELOC or home equity loan

Example: Your home is appraised at $500,000. You owe $275,000 on your primary mortgage. Your lender allows 80% CLTV.

• $500,000 × 0.80 = $400,000 (total allowable debt)
• $400,000 − $275,000 = $125,000 accessible

Run the same math at 85% CLTV and the result is $150,000. That 5% difference in the lender's policy is worth $25,000 in this example — which is why shopping lenders matters.

What "Tappable Equity" Actually Means

The financial industry uses the term "tappable equity" to describe equity you can borrow while still maintaining a 20% cushion. Across the US, tappable equity per mortgage holder stands at roughly $204,000 to $213,000 as of 2026 — but that's a national average. Your specific number depends on your home's current appraised value (not the Zillow estimate) and your exact mortgage balance.

The distinction between your total equity and your tappable equity is often where expectations collide with reality. A homeowner with $300,000 in total equity might only have $150,000 available to borrow once the CLTV constraint is applied.

Why the Appraisal Number Is What Matters

Your home's value for HELOC purposes is whatever the lender's appraisal says — not the tax assessment, not Zillow, not what you paid. If an automated valuation model (AVM) returns a number lower than you expect, the accessible equity calculation adjusts immediately downward.

This is the most common source of surprise. A homeowner runs the math in their head using Zillow's estimate, gets pre-approved for less, and thinks the lender made a mistake. They didn't — they used a different (often more conservative) value for the property.

Digital-first lenders like Figure use AVM technology that can process valuations in minutes, which speeds up approval significantly. Traditional banks often require a full appraisal ($300 to $500, taking a few weeks) for larger lines or refinances.

How to Use This as a Quick Calculator

Before applying anywhere, calculate your floor and ceiling:

1. Conservative estimate (80% CLTV): (Home value × 0.80) − mortgage balance
2. Aggressive estimate (85% CLTV): (Home value × 0.85) − mortgage balance
3. Credit union estimate (90% CLTV): (Home value × 0.90) − mortgage balance — some credit unions allow this for top-tier borrowers

Your real approval will land somewhere in that range, depending on your credit score, debt-to-income ratio, and the lender's risk appetite.

If your CLTV math puts you above 80% even before a new loan, you're in a tight spot. You'll need to pay down your mortgage, wait for appreciation, or find a specialty lender willing to go higher (at a cost).

What Affects the Calculation Beyond Math

A few factors that shift the accessible equity figure:

Property type: Investment properties and second homes get tighter CLTV limits — typically 65% to 75% for investment properties versus 80% to 85% for a primary residence. Jumping from a primary to an investment property context can cut your accessible equity nearly in half.

Credit score: Lenders who advertise 85% CLTV often apply that limit only to borrowers with FICO scores above 740. Borrowers in the 620 to 679 range may find the effective CLTV cap is 80% or lower.

Jumbo lines: Lines above $400,000 to $500,000 are typically classified as jumbo HELOCs. Maximum CLTV drops to 75% to 80%, and some lenders require an existing banking relationship.

Simultaneous second homes: If you're trying to pull equity from a property you don't live in, the bank treats the entire collateral picture more conservatively.

What to Do With This Number

Once you know your approximate borrowing capacity, the next question is what product makes sense — a HELOC (revolving line), a home equity loan (lump sum), or a cash-out refinance. The right answer depends on whether your need is a one-time expense or ongoing, and critically, what rate you're already locked into on your primary mortgage.

For homeowners holding mortgages below 4% from 2020 to 2021, replacing that rate with a new 6.5% to 7.0% cash-out refinance is mathematically expensive. A HELOC or home equity loan preserves the primary mortgage while still unlocking capital.

The Home Equity & HELOC Planning Guide walks through the full CLTV calculation, draws the comparison between all three products, and includes a structured framework for deciding which option fits your situation — covering credit requirements, closing cost analysis, and how to evaluate lenders.

The Number That Often Surprises People

U.S. homeowners collectively hold $34.5 trillion in home equity as of 2026. Of that, roughly $11.2 to $17.8 trillion is classified as tappable. The average account balance on open HELOCs is only about $8,400 to $8,700 — far below what most borrowers are approved for.

That gap suggests most homeowners open a HELOC as a safety net or for targeted use rather than drawing the maximum. That's usually the right instinct. The mathematical ability to borrow $200,000 doesn't mean borrowing $200,000 is wise — especially when the same house secures the debt and any drop in home values could freeze the line entirely.

Know your number. Plan the deployment before you apply.