What is home equity and how do you calculate it?

By King of HELOC Editorial · Reviewed by Luke Orren, Head of Content · Last updated

Home equity is the difference between your home's current market value and the total amount you still owe on it. Formula: equity = market value minus outstanding mortgage balance. It grows as you pay down your loan and as your home appreciates. Lenders typically let you borrow against up to 80–90% of that equity through products like a HELOC.

What exactly is home equity?

Home equity is the share of your home that you own outright — the portion not claimed by a lender. Think of it as the difference between what your home is worth today and what you still owe on it.

The formula is straightforward:

Home equity = Current market value − Total outstanding mortgage balance(s)

If your home is worth $400,000 and you have a remaining mortgage balance of $250,000, your equity is $150,000. That $150,000 is real financial value you have built up — and it can be put to work through products like a HELOC.

How does home equity grow?

Equity builds from two directions at once, and both work in your favor over the long run.

1. Paying down your mortgage

Every monthly payment you make chips away at your principal balance. Early in a standard amortizing mortgage, most of each payment goes toward interest, but the portion reducing principal grows over time. After 10 years of payments on a 30-year mortgage, you have meaningfully lowered the balance — and raised your equity stake.

2. Home price appreciation

When property values in your area rise, your equity increases even if you have not made a single extra payment. A home you bought for $350,000 that is now appraised at $420,000 has given you $70,000 in equity purely from market movement. Of course, home values can also fall, which would work in reverse.

Both forces — debt paydown and appreciation — typically compound over the years homeowners stay in a property.

How is home equity different from home value?

It is easy to confuse the two, but they are distinct concepts.

TermWhat it meansExample
Home value (or market value)The price your home would sell for today$400,000
Mortgage balanceWhat you still owe the lender$250,000
Home equityYour ownership stake (value minus balance)$150,000
Equity percentageEquity as a share of value37.5%

Your home’s value belongs partly to you and partly to the lender until the mortgage is paid off. Equity is only the portion that is yours.

What is loan-to-value ratio, and why does it matter?

Lenders use the loan-to-value (LTV) ratio to measure risk. It is your mortgage balance expressed as a percentage of your home’s value.

LTV = Mortgage balance ÷ Home value × 100

Using the example above: $250,000 ÷ $400,000 = 62.5% LTV.

When you want to borrow against your equity — through a HELOC or a home equity loan — lenders look at a related figure called the combined loan-to-value (CLTV) ratio, which adds any new borrowing to your existing balance. Most lenders set a maximum CLTV of 80–85%, meaning you can typically access equity down to that threshold.

How much equity can you actually borrow?

Here is a practical example showing how lenders calculate the maximum you could borrow:

The full $150,000 in equity is yours on paper, but lenders typically require you to keep a cushion — often at least 15–20% of the home’s value — as a buffer against market fluctuations.

Why home equity matters to homeowners

Equity is not just a number on a statement. It represents financial optionality:

Understanding your equity position is the first step toward deciding whether a HELOC makes sense for your situation.

How to get a reliable estimate of your home’s value

Your equity calculation is only as good as the home value you plug in. A few ways to estimate it:

  1. Automated valuation models (AVMs). Tools like Zillow’s Zestimate or Redfin’s estimate give a quick ballpark based on comparable sales. They can be off by a meaningful margin, so treat them as a starting point, not a final answer.
  2. Comparative market analysis (CMA). A local real estate agent can pull recent sales of similar homes in your neighborhood — often a more accurate picture.
  3. Professional appraisal. When you apply for a HELOC, the lender will typically order a formal appraisal. This is the number that ultimately matters for qualifying.

Knowing your approximate equity range before you apply gives you a realistic sense of how much you might be able to access and helps you compare lender offers with confidence.

Frequently asked questions

How do I calculate my home equity?

Subtract your outstanding mortgage balance (and any other liens) from your home's current market value. For example, a home worth $400,000 with a $250,000 mortgage has $150,000 in equity.

Does home equity go up automatically over time?

It can grow in two ways: your home's market value rising and your loan balance falling as you make payments. Both can happen simultaneously, but home values can also decrease, which would reduce your equity.

What percentage of my equity can I borrow against?

Most lenders allow you to borrow up to 80–85% of your home's value, less what you owe. This combined loan-to-value (CLTV) limit determines your maximum HELOC or home equity loan amount.