How much can you borrow with a HELOC?

Most lenders cap your total home debt (existing mortgage + HELOC) at 80–85% of your home's appraised value — this is called your combined loan-to-value (CLTV) limit. If your home is appraised at $500,000 and you owe $300,000, an 85% CLTV cap means your HELOC ceiling is roughly $125,000.

Your HELOC credit limit is determined by a formula, not negotiation. According to the CFPB, lenders typically set your maximum at 85% of your home's appraised value minus your outstanding first mortgage balance. Your credit score, income, and DTI can then push that number down from the mathematical ceiling.

The CLTV formula explained

Combined loan-to-value (CLTV) = (first mortgage balance + HELOC limit) ÷ appraised value. Lenders set a maximum CLTV — commonly 80% or 85%. Here is how the math works:

Home appraised at $400,000 × 85% CLTV cap = $340,000 maximum total debt
Subtract your existing mortgage balance of $250,000
Maximum HELOC = $90,000
If your lender caps at 80% instead: $320,000 − $250,000 = $70,000 maximum

What can lower your actual limit

Even if the equity math supports a high limit, lenders can pull it back based on risk factors. A lower credit score or higher DTI typically results in a more conservative CLTV cap or a flat dollar cap. Property type also matters — lenders often apply a lower CLTV to investment properties or second homes than to primary residences.

Credit score below 680: many lenders reduce the maximum CLTV to 75–80%
High DTI (above 43%): may result in a lower approved limit even if equity supports more
Investment or vacation property: typically capped at a lower CLTV than a primary home
Property condition: a low appraisal (relative to your estimate) directly reduces the available equity the formula can work with
Recent late payments or derogatory marks: can trigger manual underwriting with more conservative limits

Is the limit the same as what you should draw?

Your approved credit limit and what you should actually borrow are two different questions. Drawing up to your maximum leaves you with minimal equity cushion — if home values decline, you could end up underwater. Financial regulators have consistently advised homeowners to treat HELOCs as structured borrowing tools, not as a way to cash out all available equity. A practical rule: keep your CLTV below 80% even after draws, giving you a buffer against value fluctuations.

HELOC limits by the numbers

The CFPB states that most lenders set a HELOC credit limit at 85% of the home's appraised value minus the balance owed on the mortgage. — CFPB — What is a home equity line of credit (HELOC)?
Federal Reserve data tracks aggregate home equity loan and HELOC balances outstanding, reflecting how much American homeowners collectively borrow against their homes. — Federal Reserve — Financial Accounts of the United States (Z.1)
The CFPB notes that the total costs of a home equity line depend on the amount borrowed, the interest rate, and the length of the plan — and that drawing a large portion of a HELOC early can accelerate interest costs. — CFPB — Home equity plans: what you should know

Key takeaways

The formula is simple: (appraised value × lender's CLTV cap) minus your mortgage balance = maximum HELOC.
Most lenders use an 80–85% CLTV cap; lower credit scores or investment properties may push that down.
A professional appraisal drives the math — an inflated self-estimate won't change the lender's number.
Your approved limit and your ideal draw amount are different; staying below 80% CLTV protects you if values dip.
Shopping 2–3 lenders is worth the effort — CLTV caps and fees vary meaningfully between institutions.