How to Calculate Your Home Equity for Borrowing

Home equity is simply the portion of your home you own outright—the difference between what your home is worth today and what you still owe the lender. It's the stake you've built up through mortgage payments and any appreciation in value. Calculating it is straightforward math, but getting the inputs right matters because lenders use this number to decide how much you can borrow and at what rate.

The Basic Formula

Home equity = Current home value − Outstanding mortgage balance. That's it. If your home is worth $400,000 and you owe $250,000 on your mortgage, your equity is $150,000. The challenge isn't the math—it's nailing down accurate numbers for both sides of the equation.

Finding Your Home's Current Value

You need a realistic estimate of what your home would sell for today, not what you paid for it or what you think it's worth. Three common approaches work well:

• Professional appraisal: A licensed appraiser visits your home, inspects comparable sales, and produces an official valuation. This costs $300–$600 but is the gold standard lenders trust most.
• Automated valuation models (AVMs): Tools like Zillow's Zestimate, Redfin, or your county assessor's website give you a quick, free estimate. These are convenient but can miss local details and be off by 5–10%.
• Comparable sales analysis: Look at recent sales of similar homes in your neighborhood—same size, condition, and location. Real estate sites and local MLS data make this easy and give you a feel for the market.

For borrowing purposes, lenders often order their own appraisal or use their preferred valuation service, so don't rely solely on your own estimate. But calculating your equity on your own, a professional appraisal or a combination of public data gives you a solid starting point.

Knowing Your Mortgage Balance

This is the easier half. Your current mortgage balance is on your latest loan statement, your lender's online portal, or a quick call to your servicer. It's what you'd owe if you paid off the loan today. Don't confuse it with your original loan amount—after years of payments, the balance shrinks. If you have a second mortgage or home equity line of credit already open, include those balances too, since they reduce your available equity.

The Borrowing Limit: Loan-to-Value Ratio

Lenders don't let you borrow every dollar of equity. They use a loan-to-value (LTV) ratio to stay safe. Most will lend up to 80% of your home's value on a first mortgage, or 90% if you're willing to pay for mortgage insurance. For HELOCs and home equity loans, the typical cap is 80–90% of equity after your existing mortgage.

Here's a worked example: Your home is worth $400,000 and you owe $250,000 on your mortgage. Your equity is $150,000. At an 80% LTV on the home's total value, you could borrow up to $320,000 total (80% of $400,000). Subtract what you already owe ($250,000), and you have $70,000 available to borrow. If the lender uses 85% LTV, that available amount rises to $90,000.

Why This Matters and When to Calculate It

Knowing your equity tells you whether borrowing is even an option and shapes the terms you'll get. Lenders see high equity as low risk—you have skin in the game and less incentive to walk away. That translates to lower interest rates and better approval odds. Low equity means higher rates and stricter requirements. Calculate your equity before shopping for a HELOC, home equity loan, or refinance. It also helps if you're considering a cash-out refinance, selling, or planning a major renovation you might finance.

Market shifts matter too. If your home's value drops, so does your available equity, even if your mortgage balance stays the same. During downturns, some borrowers end up underwater—owing more than the home is worth. Conversely, a strong market can unlock thousands in borrowing power without you doing anything.