home equity line of credit calculator

What this home equity line of credit calculator does

A HELOC is a revolving line of credit secured by your home. This calculator helps you estimate two things quickly: (1) your potential credit limit based on your equity and lender CLTV cap, and (2) your monthly payment under common HELOC structures.

Most lenders look at your home value, your remaining mortgage balance, your credit profile, and your debt-to-income ratio. This page focuses on the part you can estimate right now: equity-based borrowing power.

How the calculator works

1) Estimate maximum combined borrowing

The lender’s CLTV cap determines how much total debt they allow against your home:

• Maximum combined debt = Home value × CLTV cap
• Estimated available HELOC = Maximum combined debt − Current mortgage balance

If this number is zero or negative, you likely do not have borrowable equity under that CLTV limit.

2) Estimate your monthly payment

HELOCs commonly have two phases:

• Draw period: You may be able to borrow, repay, and borrow again. Many lenders allow interest-only payments in this phase.
• Repayment period: Borrowing ends, and the outstanding balance amortizes over a set number of years.

This calculator shows both a simple interest-only estimate and a fully amortized estimate so you can compare “best-case payment today” versus “possible payment later.”

Input guide: what each field means

Current home value

Use a realistic estimate based on recent comparable sales or a professional appraisal if you have one. Overestimating value can make your available credit look larger than what a lender may actually approve.

Current mortgage balance

Use the payoff balance (or your most recent statement balance if payoff amount isn’t available). This number directly reduces your available HELOC amount.

Maximum CLTV

CLTV stands for combined loan-to-value ratio. If a lender allows 85% CLTV and your home is worth $500,000, your maximum combined debt might be around $425,000.

Requested line amount

If you enter a requested amount, the calculator compares it against your estimated maximum and reports the lower of the two. If left blank, it uses the full estimated available line.

Example HELOC scenario

Suppose your home value is $500,000, mortgage balance is $280,000, and lender CLTV cap is 85%:

• Maximum combined debt: $500,000 × 0.85 = $425,000
• Estimated available line: $425,000 − $280,000 = $145,000

If your rate is 8.5%, an interest-only monthly payment on a fully drawn $145,000 could be about $1,027 per month. If amortized over 20 years, monthly principal + interest would be higher than draw-period interest-only in many cases.

HELOC planning tips before you borrow

• Stress test your budget: HELOC rates are often variable, so payments can rise when rates rise.
• Borrow only what you need: Just because a line is available does not mean it should be fully used.
• Understand fees: Some HELOCs include appraisal, annual, inactivity, or early-closure fees.
• Ask about rate caps: Know your floor, cap, and margin over prime.
• Prepare for repayment phase: The payment jump can be significant when principal repayment starts.

HELOC vs. cash-out refinance (quick comparison)

HELOC can be better when:

• You need flexible, staged access to funds.
• You want to keep your existing first-mortgage rate.
• You value revolving credit for ongoing projects.

Cash-out refinance can be better when:

• You want one fixed payment and predictable payoff timeline.
• You can secure a favorable refinance rate and term.
• You prefer not to manage variable-rate exposure.

Important limitations

This calculator provides an estimate, not a loan offer. Final approval depends on credit score, income documentation, debt-to-income ratio, occupancy type, property type, and underwriting rules at the time of application.

Rates and terms vary by lender and region. Use this as a planning tool, then compare real quotes from multiple lenders before making a decision.