Home Equity / HELOC Calculator

How This Calculator Works

Home equity is the portion of your home’s value you own outright — its current value minus what you still owe on the mortgage. Enter your home’s current value, your remaining mortgage balance, and the maximum combined loan-to-value (LTV) ratio a lender allows, and this calculator shows both your total equity and how much of it you could actually borrow against with a home equity loan or HELOC.

Lenders don’t let you borrow against 100% of your equity — they cap combined borrowing (your existing mortgage plus any new home-equity loan) at a maximum loan-to-value ratio, commonly 75-85% depending on the lender, your credit, and local market conditions. This calculator uses that maximum LTV as a plain adjustable input rather than assuming one specific lender’s rule — check with actual lenders for the exact limit they’d offer you.

The Formula

$$\text{Home Equity} = \vA{\text{Home Value}} - \vB{\text{Mortgage Balance}}$$ $$\vD{\text{Max Combined Loan Amount}} = \vA{\text{Home Value}} \times (\vC{\text{Max LTV}} \div 100)$$ $$\text{Available to Borrow} = \vD{\text{Max Combined Loan Amount}} - \vB{\text{Mortgage Balance}}$$

Worked Example

A home worth $400,000 with a $250,000 remaining mortgage balance, at an 80% maximum loan-to-value:

1. Home equity: $\vA{400{,}000} - \vB{250{,}000} = \$150{,}000$.
2. Max combined loan amount: $\vA{400{,}000} \times 0.80 = \vD{\$320{,}000}$.
3. Available to borrow: $\vD{320{,}000} - \vB{250{,}000} = \$70{,}000$.

Estimating a Monthly Payment

Once you know how much you could borrow, the “Estimate My Monthly Payment” section answers the natural follow-up: what would a loan of a specific size actually cost per month? Enter a desired loan amount, interest rate, and term, and this calculator applies the standard fixed-rate amortization formula — the same one behind the Mortgage, Loan, and Refinance calculators — to show the monthly payment, total interest, and total paid over the life of the loan, plus whether your desired amount fits within what a lender would typically allow.

Common Mistakes

• Confusing a home equity loan/HELOC with a full refinance. A home equity product is a second loan alongside your existing mortgage, not a replacement for it — your original mortgage rate and payment stay exactly as they were.
• Assuming the maximum allowed ratio is automatically approved. Lenders commonly cap combined loan-to-value (existing mortgage + new borrowing, relative to home value) around 80-85%, but that ceiling is a guideline, not a guarantee — actual approval also depends on credit, income, and the lender’s own overlays.
• Forgetting a HELOC’s rate is often variable. Unlike a fixed-rate home equity loan, a HELOC’s rate can change over its draw period — the monthly payment estimate here assumes a fixed rate for simplicity, which may not match a variable-rate HELOC’s real payment over time.