Home Equity Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: August 19, 2026Equity Is What's Actually Yours
The price a home would sell for and the amount its owner actually has are two very different numbers once a mortgage is in the picture. Home equity is the gap between them — the portion of the property's value that belongs to the owner outright, unencumbered by any lien — and it's the figure that determines borrowing power, sale proceeds, and net worth, not the home's sticker value alone.
The Formula
Equity % = (Home Equity / Home Value) × 100
The calculator also reports the complementary loan-to-value figure — total debt as a percentage of home value — since equity and LTV are two views of the same split.
Where This Calculation Matters
- Qualifying for a HELOC or home equity loan — lenders cap how much they'll advance based on a combined loan-to-value ratio, so knowing current equity is the first step before applying.
- Deciding whether to sell — equity minus estimated selling costs is the actual cash a sale would put in your pocket, which can be very different from the home's listed value.
- Tracking mortgage payoff progress — equity grows both from principal payments and from price appreciation, and separating the two shows how much is coming from each.
- Avoiding being underwater — when other liens plus the mortgage balance exceed home value, equity goes negative, a position worth identifying before making other financial decisions tied to the home.
Equity Buildup as a Mortgage Amortizes
On a $400,000 home with no change in market value, here's how equity and loan-to-value shift purely as the mortgage balance is paid down:
| Mortgage balance | Equity | Equity % | LTV |
|---|---|---|---|
| $380,000 | $20,000 | 5.0% | 95.0% |
| $300,000 | $100,000 | 25.0% | 75.0% |
| $200,000 | $200,000 | 50.0% | 50.0% |
| $100,000 | $300,000 | 75.0% | 25.0% |
| $0 | $400,000 | 100.0% | 0.0% |
How to Use This Calculator
- Enter the current Home Value (an appraisal or a reasonable market estimate).
- Enter the outstanding Mortgage Balance.
- Enter any Other Liens (a second mortgage, a home equity loan, an unpaid tax lien) if applicable.
- Select Calculate to see your equity in dollars, as a percentage of home value, and the corresponding loan-to-value ratio.
Related Calculations
Turn available equity into borrowing capacity with the HELOC Calculator, or see what a cash-out refinance could extract with the Cash-out Refinance Calculator.
Principles of Residential Real Estate Finance and Home Equity Borrowing
A home equity calculator computes current unencumbered home equity value, Combined Loan-to-Value (CLTV) ratios, and maximum borrowing capacity for Home Equity Lines of Credit (HELOC), Home Equity Loans (HELOAN), and Cash-Out Refinances. In personal financial planning and mortgage underwriting, home equity serves as a prime source of low-interest collateralized capital for home renovations and debt consolidation.
The Fundamental Home Equity Formulas
Loan-to-Value Ratio: LTV (%) = ( Primary Mortgage Balance / Appraised Value ) × 100%
Combined LTV: CLTV (%) = [ ( Primary Mortgage + Secondary Liens / HELOC Limit ) / Appraised Value ] × 100%
Maximum Borrowing Capacity = ( Appraised Value × Max Allowed CLTV % [typically 80% to 85%] ) - Current Mortgage Balance
Comparison of Home Equity Financing Options
| Financing Product | Interest Rate Structure | Disbursement & Repayment Mechanics |
|---|---|---|
| Home Equity Loan (HELOAN) | Fixed Interest Rate | Lump-sum upfront cash payout; fixed monthly principal & interest payments over 5 to 30 years |
| Home Equity Line of Credit (HELOC) | Variable Rate (Prime + Margin) | Revolving credit line; 10-year interest-only draw period followed by 20-year full amortizing repayment |
| Cash-Out Refinance | Fixed or Adjustable | Replaces entire primary mortgage with a new, larger loan, paying out equity difference in cash |
Step-by-Step Worked Calculation Example
Example: Calculating Maximum HELOC Borrowing on a $500,000 Home
Problem: A homeowner owns a property appraised at $500,000 with a remaining first mortgage balance of $280,000. A lender approves a HELOC up to an 80.0% Maximum Combined Loan-to-Value (CLTV) limit. Calculate: (1) Total current unencumbered home equity; (2) Current primary LTV; and (3) Maximum available HELOC credit line.
Step 1: Calculate Total Current Home Equity:
Home Equity = $500,000 (Appraised Value) - $280,000 (Mortgage Balance) = $220,000.00
Step 2: Calculate Current LTV:
LTV = ( $280,000 / $500,000 ) × 100% = 56.0% LTV
Step 3: Calculate Maximum Total Allowed Debt (80% CLTV Cap):
Max Allowed Debt = $500,000 × 0.80 = $400,000.00
Step 4: Compute Maximum Available HELOC Credit Line:
Max HELOC Line = $400,000 - $280,000 (Existing Mortgage) = $120,000.00
Conclusion: The homeowner holds $220,000 in equity and can access a maximum $120,000 HELOC line at 80% CLTV.
Tax Deductibility of Home Equity Interest (IRS Section 163)
Under the federal Tax Cuts and Jobs Act (TCJA), interest paid on HELOCs and Home Equity Loans is tax-deductible only if the borrowed funds are used to "buy, build, or substantially improve" the home securing the loan (such as adding a bathroom or replacing a roof).
Using home equity to pay off credit card debt, purchase a new automobile, or fund personal vacations renders the interest 100% non-deductible on IRS Form 1040 Schedule A.
Debt-to-Income (DTI) Mortgage Underwriting Limits
Mortgage lenders evaluate borrowing risk using the Debt-to-Income Ratio (DTI):
Most prime lenders cap maximum allowable back-end DTI at 43.0% to 45.0% to approve a new HELOC or second mortgage loan.
HELOC Draw Period vs. Repayment Period Shock
Homeowners utilizing a HELOC must prepare for the End-of-Draw Payment Shock:
- Draw Period (Years 1 to 10): Borrowers make low, interest-only monthly payments on the drawn balance.
- Repayment Period (Years 11 to 30): The credit line freezes, and the loan converts into a fully amortizing 20-year principal and interest repayment schedule, doubling or tripling the required monthly payment.
Automated Valuation Models (AVM) vs. Full Appraisals
When applying for a home equity line, lenders determine property market value using either:
- Automated Valuation Model (AVM): Instant computer algorithmic property valuation based on recent neighborhood comparable sales, eliminating the $400 to $600 full appraisal fee.
- Full Interior/Exterior Appraisal: Required for jumbo loan amounts exceeding $250,000 or unique custom rural properties.
Subordination Agreements in Home Equity Refinancing
When refinancing a primary first mortgage while retaining an existing HELOC, the HELOC lender must sign a Subordination Agreement agreeing to remain in second-lien priority position; failure to secure subordination requires paying off and closing the HELOC.
Fixed-Rate Conversion Options on Variable HELOCs
Many lending institutions allow borrowers to lock in a fixed interest rate on specific portions of their drawn HELOC balance (a "Fixed-Rate Lock Option"), protecting against rising Federal Reserve interest rate hikes.
Lender Early Closure Penalty Fees
Many banks charge a $350 to $500 early closure fee if a homeowner cancels and closes their HELOC account within the first 24 to 36 months.