Finance calculators

HELOC Interest Only Payment Calculator

Updated Sep 1, 2026 By Jehan Wadia
Rate Formulas
Your HELOC Details

The amount you have actually drawn — not your total credit limit.

Enter the rate your lender discloses, e.g. 7.25.

Years you pay interest only. Typically 5–10 years.

Years to pay off the balance after the draw period. Often 10–20 years.

Payment Jump: Draw Period vs. Repayment Period

Draw period (Years 1–10) $906.25 per month — interest only
Monthly increase $463.26 +51.12%
Repayment period (Years 11–25) $1,369.51 per month — principal + interest

Draw Period Results

Monthly Interest-Only Payment
$906.25
Total interest paid during draw period $108,750.00
Number of interest-only payments 120
Balance owed when draw period ends $150,000.00

Repayment Period Results

Monthly Principal + Interest Payment
$1,369.51
Total interest paid during repayment $96,511.80
Number of repayment payments 180
Total paid during repayment period $246,511.80

Lifetime Summary

Total Interest Paid (Full Loan)
$205,261.80
Total Amount Paid (Full Loan)
$355,261.80
Interest as % of Balance Drawn 136.84%
Total Loan Length 25 yrs

Step-by-Step Solution

Monthly Payment Comparison

Where Your Lifetime Payments Go

Balance & Cumulative Interest by Year

Year-by-Year Schedule

Year Phase Monthly Payment Interest This Year Principal This Year Ending Balance Cumulative Interest

Introduction

A HELOC (home equity line of credit) lets you borrow against the value of your home. Most HELOCs have two stages. First comes the draw period, when you can borrow money and pay only the interest each month. Then comes the repayment period, when you must pay back the interest and the money you borrowed.

This HELOC interest only payment calculator shows you both payments. Enter how much you have drawn, your interest rate, and the length of each period. You will see your monthly interest-only payment, your future principal and interest payment, and the total interest you will pay over the life of the loan.

The big thing to watch is the payment jump. When the draw period ends, your monthly bill can rise a lot, often by hundreds of dollars. This tool shows that jump in plain numbers, plus a year-by-year schedule, charts, and step-by-step math so you can see exactly how each figure was found. Use it to plan ahead so the higher payment does not catch you by surprise.

How to use our HELOC Interest Only Payment Calculator

Enter four details about your home equity line of credit, and the calculator shows your interest-only payment during the draw period, your higher principal and interest payment after it ends, the total interest you pay, and a year-by-year schedule.

HELOC Balance Drawn: Type the amount of money you have taken out, not your full credit limit. Interest is charged only on what you use. Example: 150,000.

Annual Interest Rate (APR): Type the yearly rate your lender gave you, such as 7.25. HELOC rates often change, so use your current rate to see today's cost.

Draw Period Length: Type how many years you can borrow and pay interest only. Most HELOCs use 5 to 10 years. Your balance stays the same during this time.

Repayment Period Length: Type how many years you have to pay the balance down to zero after the draw period ends. Most lenders use 10 to 20 years. A longer term lowers the monthly payment but costs more interest.

Calculate and Reset: Results update as you type, but you can click Calculate to refresh them. Click Reset to go back to the sample numbers and start over.

What Is a HELOC Interest-Only Payment?

A HELOC is a home equity line of credit. It lets you borrow against the value of your home, a bit at a time, like a credit card. In the first few years, called the draw period, most lenders only make you pay the interest each month. That keeps your payment small, but your loan balance does not go down at all. If you would rather borrow a fixed lump sum with steady payments, compare it against a Home Equity Loan Calculator.

How the Two Periods Work

Draw period: This usually lasts 5 to 10 years. You can borrow money from your line and pay back only the interest. Your payment is simply your balance times your monthly interest rate. If you pay only the interest, you still owe the full amount you borrowed when this period ends.

Repayment period: This often lasts 10 to 20 years. You can no longer borrow. Now your payment covers both interest and principal, so the loan reaches zero by the end. Because you are paying off the whole balance in fewer years, the payment goes up, often by a lot. The formula is the same one used by our Mortgage Calculator.

Payment Shock

The jump from an interest-only payment to a full principal-and-interest payment is called payment shock. It can easily add hundreds of dollars to your monthly bill. Many people are caught off guard because nothing changed with their home or their rate. Only the payment rules changed. Knowing the future payment ahead of time helps you plan, save, or pay extra early.

Why Interest-Only Payments Cost More Over Time

Interest-only payments feel cheap, but every dollar is pure cost. None of it lowers your debt. If you owe $150,000 at 7.25% and pay interest only for 10 years, you hand the lender about $108,750 and still owe the full $150,000. Paying even a little extra toward principal during the draw period lowers your balance, cuts your interest, and shrinks the payment jump later.

Watch the Variable Rate

Most HELOC rates are variable. They are tied to the prime rate, so they move up or down with the market. If rates rise, your interest-only payment rises too, even though your balance stayed the same. This tool holds one rate steady, so it helps to test a higher rate as well to see the worst case.

Smart Ways to Use This Information

  • Compare your interest-only payment to your future full payment before you borrow.
  • Pay extra principal during the draw period to lower both the balance and the shock.
  • Check the total interest over the full loan, not just the monthly amount.
  • If the HELOC is one of several debts, map out an order of attack.
  • Remember your home is the collateral. Missing payments can put it at risk.

Formulas used

Monthly interest rate from APR
r = \frac{\text{APR}\%/100}{12}
Monthly interest-only payment (draw period)
\text{IO} = P \times r
Total interest paid during draw period
I_{\text{draw}} = \text{IO} \times (t_{\text{draw}} \times 12)
Monthly principal + interest payment (repayment period)
M = P \cdot \frac{r(1+r)^{n}}{(1+r)^{n}-1}, \qquad n = t_{\text{repay}} \times 12
Monthly payment when rate is 0%
M = \frac{P}{n}
Total interest paid during repayment period
I_{\text{repay}} = (M \times n) - P
Payment jump at end of draw period
\Delta = M - \text{IO}, \qquad \Delta\% = \frac{M - \text{IO}}{\text{IO}} \times 100
Lifetime totals and interest as percent of balance
I_{\text{total}} = I_{\text{draw}} + I_{\text{repay}}, \quad \text{Total Paid} = I_{\text{total}} + P, \quad \text{Int\%} = \frac{I_{\text{total}}}{P} \times 100

Frequently asked questions

How is the interest-only payment worked out?

The calculator takes your balance and multiplies it by your monthly rate. The monthly rate is your APR divided by 12.

Example: $150,000 × (7.25% ÷ 12) = $906.25 per month.

Why is my real HELOC bill a few dollars different?

Many lenders charge daily interest on your average daily balance. That makes each bill change a little with the number of days in the month.

This tool uses a clean monthly rate, so treat the result as a close estimate, not an exact statement.

Does this include fees or closing costs?

No. It shows only principal and interest. HELOCs can also have annual fees, yearly account fees, appraisal costs, or early closing fees. Ask your lender and add those on top.

Can I put 0% in the rate box?

Yes. The tool then shows a $0 interest-only payment and splits the balance evenly across the repayment months. You will see a note that a 0% HELOC is unusual.

What numbers should I use if I don't know my terms yet?

  • Draw period: 10 years
  • Repayment period: 15 or 20 years
  • Rate: your lender's current quote

These match most common HELOC offers in the U.S.

Why is my total interest bigger than the amount I borrowed?

Because you pay interest for many years. Ten years of interest-only payments add up fast, and you still owe the full balance after them.

At $150,000 and 7.25% over 10 + 15 years, total interest is about $205,000, which is more than the loan itself.

How can I make the payment jump smaller?

  • Pay extra toward principal during the draw period.
  • Draw less than your full limit.
  • Ask for a longer repayment term.
  • Refinance into a fixed-rate loan before the draw period ends.

What if I can't afford the higher repayment payment?

Act early, before the draw period ends. You can refinance the HELOC, roll it into a new first mortgage, or ask your lender about a new draw period.

Your home is the security for this loan, so do not wait until you miss a payment.

Do some HELOCs end with one big balloon payment?

Yes. A few HELOCs have no repayment period at all. The whole balance is due when the draw period ends.

This calculator models the common two-stage loan. Check your paperwork for the word "balloon" so you know which type you have.

Is HELOC interest tax deductible?

Sometimes. Under current IRS rules, interest may be deductible if the money buys, builds, or greatly improves the home that secures the loan. Limits apply. Ask a tax pro, since this calculator shows pre-tax numbers.

Can my lender cut my line during the draw period?

Yes. Lenders can freeze or lower a HELOC if home values drop or your finances change. You still owe what you already drew, so do not count on future draws as your safety net.

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