What is HELOC Calculator?
A HELOC (Home Equity Line of Credit) calculator helps you estimate the monthly payments and total cost of a home equity line of credit. Unlike a traditional home equity loan that provides a lump sum, a HELOC works like a credit card secured by your home — you can borrow as needed up to your credit limit during the draw period, then repay over the repayment period.
This calculator models both the draw period (interest-only payments) and the repayment period (principal + interest amortization). It shows your monthly payment, total interest, and a year-by-year breakdown so you can understand the full cost of borrowing against your home equity.
Key factors affecting your HELOC cost include the interest rate (typically variable, based on prime rate + margin), draw period length (usually 10 years), repayment period (usually 20 years), and closing costs (2-5% of the credit line).
Steps:
- Enter the HELOC amount you plan to borrow.
- Enter the current interest rate (variable, based on prime + margin).
- Enter the total term (draw period + repayment period).
- Enter estimated closing costs (typically 2-5% of loan amount).
- Enter your home's current value and existing mortgage balance.
- Enter the draw period length (typically 10 years).
- Review the monthly payment, total interest, and payoff timeline.
Formula
Monthly Payment = P × [r(1+r)^n] / [(1+r)^n - 1]
Where P = loan amount, r = monthly interest rate (annual rate ÷ 12), n = total months
Draw Period Payment = Loan Amount × Monthly Rate (interest-only)
Repayment Period Payment = Amortized over remaining months
Total Interest = (Monthly Payment × Total Months) - Loan Amount - Closing Costs
Use Cases
- Estimating HELOC payments for home renovations
- Planning debt consolidation with a HELOC
- Comparing HELOC vs. home equity loan costs
- Budgeting for major expenses (education, medical, emergencies)
- Understanding the impact of variable rates on payments
Key Benefits
- Get accurate HELOC payment estimates instantly
- See draw period vs. repayment period costs clearly
- Make informed decisions about home equity borrowing
- Free on any device no downloads
Pro Tips
- Only borrow what you need to minimize interest costs
- Make extra principal payments during draw period if possible
- Monitor prime rate changes that affect your payment
- Consider a fixed-rate HELOC option if available
Common Mistakes to Avoid
- Underestimating the payment increase after draw period ends
- Borrowing more than needed during the draw period
- Ignoring variable rate risk
- Not accounting for closing costs
Key Terms Explained
- Draw Period: Time when you can borrow (interest-only payments)
- Repayment Period: Time to repay principal + interest after draw ends
- HELOC: Home Equity Line of Credit
- Prime Rate: Base rate for variable HELOCs
- LTV: Loan-to-Value ratio
Related Concepts
- Home Equity Loan Calculator – Compare lump-sum home equity loans
- Mortgage Calculator – Calculate primary mortgage payments
- Refinance Calculator – Compare refinance options
Example
You take a $50,000 HELOC at 7.5% on a $400,000 home with a $200,000 mortgage. Draw period: 10 years, repayment: 20 years. During the draw period, you pay interest-only on borrowed amounts. At $50,000 borrowed, monthly payment = $312.50 (interest-only). After 10 years, repayment begins: monthly payment = $404.50 for 20 years. Total interest over 30 years = $97,080. Closing costs of $2,500 bring total cost to $99,580.