The amount you can borrow depends on your home's value, how much you still owe, and your lender's rules

Most lenders let you borrow between 80 and 90 percent of your home's total value, minus what you still owe on your mortgage. If your home is worth $300,000 and you owe $150,000 on your mortgage, a lender using the 80 percent rule would let you borrow up to $90,000 through a HELOC (the difference between $240,000 and $150,000). The exact percentage varies by lender and by how strong your credit history and income look to them.

Your credit score, debt-to-income ratio, and employment history all affect not just whether a lender will offer you a HELOC, but how much they will let you borrow. A lender might offer one borrower 85 percent of home value while offering another only 75 percent, based on these factors. You do not know your actual limit until you apply or get a pre-qualification from a specific lender.

The amount available also depends on current market conditions and the lender's own risk appetite. During periods when lenders are cautious, they may lower the percentage of home value they will lend against, which shrinks the pool of money available to you even if your home's value has not changed.

Key Takeaways

  • Most lenders calculate your HELOC limit by taking 80 to 90 percent of your home's value and subtracting your remaining mortgage balance.
  • Your credit score, income, and existing debts affect how much a specific lender will offer you, even if the math says you could borrow more.
  • You do not have to borrow the full amount available to you — you can draw only what you need and pay interest only on what you use.
  • Your home serves as collateral, so if you cannot repay, the lender can foreclose and sell your home to recover the money.

How lenders calculate your borrowing limit

Lenders start with a number called your loan-to-value ratio, or LTV. They appraise your home, multiply that value by a percentage (usually 80 to 90 percent), then subtract what you still owe on your first mortgage. The result is your maximum HELOC limit.

Example: Your home appraises at $400,000. Your lender uses 85 percent LTV. You owe $200,000 on your mortgage.

Calculation: ($400,000 × 0.85) − $200,000 = $140,000 maximum HELOC limit.

If you have other liens on the home — a second mortgage, a tax lien, or a judgment lien — those also get subtracted before you reach your limit. A lender will not lend you money if doing so would put them behind other creditors in line.

Why your credit and income matter

Even if the math says you can borrow $140,000, your lender might offer you only $80,000 if your credit score is below 650 or if your monthly debt payments already consume a large portion of your income. Lenders use debt-to-income ratio — the percentage of your gross monthly income that goes to debt payments — to decide how much risk they are willing to take.

A lender might require your debt-to-income ratio to stay below 43 or 50 percent when you add the HELOC payment into the calculation. If you earn $5,000 per month and already pay $2,000 toward existing debts, a lender using a 43 percent threshold would not let you borrow enough to add more than $150 per month in payments. That limits how much they will lend you, regardless of your home's equity.

Employment history and income stability also factor in. Self-employed borrowers often face stricter scrutiny and lower limits than W-2 employees, because lenders view their income as less predictable. Recent job changes, gaps in employment, or income that has dropped year-over-year can all reduce the amount a lender will offer.

The difference between your limit and what you actually owe

Your HELOC limit is the maximum you can borrow, but you do not have to use it all. You draw money only when you need it, and you pay interest only on the amount you have actually borrowed. If your limit is $100,000 but you draw only $30,000, you owe interest on $30,000.

During the draw period — usually 5 to 10 years — you can borrow, repay, and borrow again, like a credit card. Once the draw period ends, the repayment period begins, and you can no longer draw new money. You then repay what you borrowed over a set number of years, typically 10 to 20 years.

Some HELOCs have a balloon payment at the end, meaning a large lump sum comes due when the draw period ends. Read the terms carefully, because this can create a serious financial squeeze if you have not planned for it.

What happens if your home value drops

If your home's value falls after you open a HELOC, your lender may freeze your account or reduce your available credit. During the 2008 housing crisis, many lenders froze HELOCs entirely, leaving borrowers unable to access money they thought they had available. Your lender has the right to do this if they believe the collateral (your home) no longer covers the risk they are taking.

If you have already borrowed money and your home value drops, you still owe what you borrowed. You cannot simply walk away. The lender can foreclose if you stop paying, just as they can on a first mortgage.

How to find out your actual limit

The only way to know what a specific lender will offer you is to contact them directly or apply for a pre-qualification. Many lenders offer free pre-qualification, which involves a soft credit check and does not affect your credit score. They will ask about your income, existing debts, and the approximate value of your home.

You can also get a rough estimate yourself by finding your home's estimated value (through Zillow, your county assessor, or a recent appraisal) and working through the math: (home value × 0.80 or 0.85) − mortgage balance = rough maximum. Keep in mind this does not account for your credit score, income, or other debts, so the actual offer may be lower.

If one lender offers you a lower limit than you expected, shop with other lenders. Different lenders use different LTV percentages, credit score thresholds, and debt-to-income limits. A second or third quote might be significantly higher.

Frequently Asked Questions

Can I borrow more than my home's equity?

No. Your HELOC limit cannot exceed the equity you have built. Equity is your home's value minus what you owe on all mortgages and liens. If your home is worth $300,000 and you owe $250,000, your maximum equity is $50,000, and no lender will offer you a HELOC larger than that.

What if I have a second mortgage — does that reduce my HELOC limit?

Yes. A second mortgage is a lien on your home, just like your first mortgage. Lenders calculate your HELOC limit by subtracting all liens from your home's value. A second mortgage reduces the equity available for a HELOC.

Can my lender lower my HELOC limit after I open it?

Yes. Lenders can reduce or freeze your available credit if your credit score drops, your home value falls, you miss payments, or economic conditions change. This happened widely during the 2008 recession. Review your account statements and lender communications to stay aware of changes.

Does the HELOC limit include my first mortgage?

No. Your HELOC limit is calculated by subtracting your first mortgage balance from your available equity. The HELOC is a separate line of credit that sits behind your first mortgage in priority.

What if I want to borrow more than my lender will offer?

You can shop with other lenders, who may have different lending standards. You can also wait for your home value to increase, which increases your equity. Alternatively, you could pay down your first mortgage to free up more equity, though this takes time and money.