How a Home Equity Calculator Works
Home equity is the share of your home that you actually own — the difference between what your home is worth and what you still owe on your mortgage. As you pay down your mortgage and your home appreciates, your equity grows. A home equity calculator turns those numbers into the figures lenders care about: your equity, your loan-to-value ratio, and how much you could borrow.
A HELOC (home equity line of credit) lets you borrow against that equity, but lenders won't let you tap all of it. They set a maximum combined loan-to-value (LTV) ratio — often around 85% — and your borrowing limit is whatever room is left under that cap after your existing mortgage. The HELOC Payment tab then shows what monthly repayment on that borrowed amount would look like.
The Home Equity Formulas
These calculations connect your home value, mortgage balance, and the lender's maximum LTV to determine your borrowing power:
- Current Equity = Home Value − Mortgage Balance
- Current LTV = Mortgage Balance ÷ Home Value × 100
- Max Borrowable = (Home Value × Max LTV) − Mortgage Balance
- Equity % = Equity ÷ Home Value × 100
How to Use Your Home Equity Wisely
Borrowing against your home can fund renovations or consolidate debt at a relatively low rate, but it adds risk because your house is the collateral. Keep these points in mind before drawing on a HELOC.
- Most lenders cap combined loan-to-value somewhere between 80% and 90% of your home value.
- HELOC interest rates are often variable, so your payment can rise if rates increase.
- Many HELOCs have an interest-only draw period followed by a higher repayment period.
- Because your home secures the loan, missing payments can put your property at risk of foreclosure.
Frequently Asked Questions
What is a good loan-to-value ratio?
A lower LTV is better because it means you have more equity and less debt relative to your home value. Lenders generally view a combined LTV under 80% as low risk, which can unlock better rates. Most home equity products allow you to borrow up to a combined LTV of about 85%, though limits vary by lender and credit profile.
How much can I borrow with a HELOC?
Your maximum HELOC is the lender's allowed LTV applied to your home value, minus your remaining mortgage balance. For example, with an 85% LTV cap on a home worth your full value, the lender lets total debt reach 85% of that value, and your existing mortgage takes up part of that room. The leftover is your borrowing limit, assuming you also qualify based on income and credit.
Is a HELOC payment fixed?
Not always. HELOCs typically carry variable interest rates, and many have an interest-only draw period where payments are lower, followed by a repayment period with higher fully amortizing payments. The HELOC Payment tab in this calculator estimates a fully amortizing fixed payment so you can gauge the long-term cost of repaying the balance.