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HELOC Calculator

Estimate your home equity line of credit (HELOC) limit, the interest-only payment during the draw period, and the higher payment once repayment starts.

Results

ItemValue

If the rate changes

RateDraw period (interest only)Repayment period
Most HELOCs have a variable rate, so payments can rise or fall. This assumes you draw the full amount at the start, pay only interest during the draw period, and then repay in equal monthly payments. Your lender’s terms may differ.

Quick Answer

A HELOC usually has two stages. During the draw period you may pay only interest: balance × rate ÷ 12. Then you repay the balance with interest. Drawing $60,000 at 8.5% costs about $425.00 a month interest-only, then about $520.69 a month over a 20-year repayment period.

Last updated: 2 November 2026 ·How we calculate this: the interest-only and fixed repayment formulas

Table of Contents

How This HELOC Calculator Works

Enter your home’s value, your mortgage balance and the lender’s maximum combined loan-to-value to see your possible credit line. Then enter how much you plan to draw, the rate, and the length of the draw and repayment periods. The calculator shows the interest-only payment, the payment once repayment starts, and how payments change if the rate moves.

Quick explanation: a HELOC works like a credit card backed by your home.

  • Draw period: borrow as needed, often paying only interest.
  • Repayment period: no more borrowing, and payments include principal.
  • Variable rate: payments can change when rates change.

How to Use the HELOC Calculator

  1. Enter your home value and mortgage balance.
  2. Enter the lender’s maximum combined loan-to-value, often 80% to 85%.
  3. Enter how much you plan to draw and the interest rate.
  4. Choose the draw and repayment periods.
  5. Press Calculate and compare the two payments and the rate table.

Core Formulas

  • Credit line: home value × max CLTV − mortgage balance
  • Interest-only payment: balance × annual rate ÷ 12
  • Repayment payment: B × r ÷ (1 − (1 + r)^−n)
  • Total interest: interest-only payments + repayment payments − balance

B is the balance at the end of the draw period, r is the monthly rate and n is the number of repayment months.

Key Terms

  • HELOC: home equity line of credit, a revolving credit line secured by your home.
  • Draw period: the years when you can borrow from the line, often 10.
  • Repayment period: the years after the draw period when you repay the balance.
  • Prime rate: a benchmark rate that many HELOC rates follow.
  • Payment shock: a big jump in payment when repayment starts or rates rise.

Worked Example

Your home is worth $350,000 and you owe $200,000. The lender allows 80% CLTV. You draw $30,000 at 7.75%, with a 5-year draw and 15-year repayment.

  • Credit line = $350,000 × 0.80 − $200,000 = $80,000.00
  • Interest-only payment = $30,000 × 7.75% ÷ 12 = $193.75
  • Repayment payment = $282.38 a month for 15 years

Real-Life Examples

  • A home project in stages: drawing $60,000 at 8.5% costs $425.00 a month interest-only, rising to $520.69 when repayment begins.
  • Planning for payment shock: the jump of $95.69 a month in that example is why it helps to pay some principal early.
  • Rate rise: if the rate goes up 2 points to 10.5%, the interest-only payment on $60,000 rises to $525.00.
  • Emergency backup: an unused line costs no interest, though some lenders charge fees.

HELOC vs Home Equity Loan

  • HELOC: a reusable credit line, usually variable rate, with interest-only payments possible in the draw period.
  • Home equity loan: a lump sum with a fixed rate and fixed payments from the start.
  • Choosing: a HELOC suits costs over time. A fixed loan suits one known cost and steady budgeting.

Interest-Only Payment per $10,000

RatePer $10,000Per $50,000Per $100,000
6%$50.00$250.00$500.00
7%$58.33$291.67$583.33
7.5%$62.50$312.50$625.00
8%$66.67$333.33$666.67
8.5%$70.83$354.17$708.33
9%$75.00$375.00$750.00
10%$83.33$416.67$833.33

What Changes Your HELOC Cost

  • Prime rate: most HELOC rates are the prime rate plus a margin, so they move with it.
  • Paying principal early: paying more than interest during the draw period lowers the later payment.
  • How much you draw: you pay interest only on what you use.
  • Fees: some HELOCs have annual, inactivity or early-closing fees.

Common Mistakes to Avoid

  • Planning only for the interest-only payment. The repayment payment can be much higher.
  • Ignoring rate changes. A variable rate can rise.
  • Treating it as extra income. It is debt secured by your home.
  • Drawing the full line. Borrow only what you need.
  • Not reading the fees. Check annual, inactivity and early-closing fees.

Frequently Asked Questions

During the draw period, interest-only payments are balance × rate ÷ 12. During repayment, the balance is paid off with equal monthly payments.

Often up to 80% to 85% of your home’s value minus your mortgage balance. Your lender sets the limit.

Usually variable. Some lenders let you lock part of the balance at a fixed rate.

Often 10 years, followed by a 10 to 20-year repayment period.

Many HELOCs allow interest-only payments, but paying some principal lowers later payments.

You can no longer borrow, and you start repaying principal and interest, or you may owe the full balance, depending on the terms.

No. You pay interest only on the amount you have drawn.

Yes. Your home secures the line, so the lender can foreclose if you do not repay.

It can be when the money is used to buy, build or substantially improve the home. Ask a tax professional.

Yes. Lenders can reduce or freeze a line, for example if your home’s value falls a lot.

HELOC rates are usually lower, but the debt is secured by your home.

Usually yes. Some lenders charge a fee if you close the line within the first few years.

References & Sources

SourceUsed ForLink
Federal Trade Commission, Home equity loans and home equity lines of credit Draw and repayment periods, and variable rates. https://consumer.ftc.gov/articles/home-equity-loans-and-home-equity-lines-credit
Consumer Financial Protection Bureau, What is a second mortgage loan? HELOCs as open-end second mortgages, and their risks. https://www.consumerfinance.gov/ask-cfpb/what-is-a-second-mortgage-loan-or-junior-lien-en-105/