A $50,000 home equity line of credit (HELOC) at 8.5% costs $354.17 a month during a 10-year interest-only draw, then $433.91 a month for 20 years of repayment. The HELOC calculator returns both payments, total interest and total paid for any balance, rate and term, plus a year-by-year table.

Examples

Monthly payment during draw (interest only)

$354.17

Borrowing $50,000 at 8.5% costs $354.17 a month interest-only for 10 years, then $433.91 a month for 20 years.

Informational only, not financial advice.

Monthly payment during draw (interest only): $354.17
Monthly payment during repayment: $433.91
Total interest: $96,638.79
Total paid: $146,638.79

Year by year

Year	Phase	Interest that year	Balance at year end

How this is calculated

How it works: The two periods, draw and repayment, follow the CFPB's HELOC booklet (opens in new window). The draw-period payment is interest only: balance × rate ÷ 12. The repayment payment is the standard amortization formula over the repayment months at a fixed rate; a variable-rate line will differ as the index moves.
Not covered: An interest-only estimate; a variable rate is not modeled; no fees or closing costs.
Privacy: Your numbers never reach our server. The math runs on your device, inside this page.
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Updates: 9 Oct 2026 Published.
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Table of Contents

How to Use the HELOC Calculator

Four inputs drive the HELOC calculator, and it runs entirely in your browser without asking for a name, email or phone number. As a HELOC payment calculator, it returns the draw-period payment, the repayment payment, total interest and total paid, plus a year-by-year table. Fill in the fields in order:

Enter the balance you expect to carry in “Amount drawn”. The tool charges interest on that figure, so use the amount you plan to borrow instead of the full credit limit.
Type the yearly rate in “Interest rate (APR)”. On a variable-rate line, use today’s rate; the tool holds it for the whole term.
Set “Draw period” to the number of interest-only years, from 0 to 30. According to the Consumer Financial Protection Bureau (CFPB), the draw period could last 10 years, for example. At 0, the draw payment shows zero.
Set “Repayment period” to the years the lender gives you to pay off the balance, from 1 to 30. Per Regulation Z, lenders must disclose the length of the draw period and any repayment period, so both numbers appear in your HELOC paperwork.

Results update as you type. “Monthly payment during draw (interest only)” leads, followed by “Monthly payment during repayment”, “Total interest” and “Total paid”. A collapsed “Year by year” table lists each year’s phase, the interest charged that year and the balance at year end.

The “Examples” row loads three presets, including the worked example below.

Two formulas sit behind those four outputs.

How HELOC Payments Are Calculated

According to the CFPB’s HELOC booklet, some plans may allow payment of the interest only, during the draw period, which means that you pay nothing toward the principal.

Draw years in the calculator follow that arrangement, so the balance stays where it started. Once repayment starts, however, the tool switches to the standard amortizing principal-and-interest payment the CFPB describes for fixed-rate mortgages.

In symbols, P is the amount drawn and r is the annual rate as a decimal. The monthly rate i is r divided by twelve, and n counts the repayment months:

Draw-period payment = P × i.
Repayment payment = P × i × (1 + i)^n ÷ ((1 + i)^n – 1).
Total interest = draw payment × draw months + repayment payment × n – P.

Per the CFPB’s mortgage amortization explainer, lenders use a standard formula to calculate the monthly payment that allows for just the right amount to go to interest and principal, to pay off the loan precisely at the end of the term.

Checking the Formula Against a CFPB Example

According to a worked case the bureau publishes, a mortgage loan of $100,000 for 30 years at an interest rate of four percent carries a monthly principal and interest payment of $477, with $90,448 still owed at the end of the fifth year on a five-year balloon version.

Set “Draw period” to 0, “Repayment period” to 30, “Amount drawn” to $100,000 and the rate to 4%, and “Monthly payment during repayment” reads $477.42 a month. Its “Year by year” table shows a year-5 balance of $90,447.51, matching the bureau’s figure to the dollar.

You can check a lender’s own paperwork the same way. Regulation Z requires HELOC disclosures to show an example, based on a $10,000 outstanding balance and a recent annual percentage rate, showing the minimum periodic payment, any balloon payment, and the time it would take to repay it.

At 8.5% with a 10-year draw and a 20-year repayment, $10,000 costs $70.83 a month, then $86.78. Because lenders have to express their terms through the same $10,000 example, it is the easiest place to compare two offers line by line.

Walking through the pinned example shows each step.

HELOC Payment Example: $50,000 at 8.5%

Loaded by default, the $50,000 preset at 8.5% with a 10-year draw and a 20-year repayment produces the intro’s $354.17 and $433.91. Seven steps turn those inputs into the result:

Monthly rate: 8.5% ÷ 12 = 0.7083% a month.
Draw payment: $50,000 × 0.00708333 = $354.17 a month, interest only.
Draw interest: $50,000 × 0.085 ÷ 12 × 120 months comes to $42,500, and the “Balance at year end” column still shows the full amount drawn after year 10.
Growth factor: (1.00708333)^240 comes to 5.441, or 5.44124 before rounding, over the 240 repayment months.
Repayment payment: $50,000 × 0.00708333 × 5.44124 ÷ 4.44124 = $433.91 a month.
Repayment interest: 240 payments at the unrounded $433.91162, less the $50,000 repaid, leave $54,138.79 of interest.
Totals: interest reaches $96,638.79, and the total paid reaches $146,638.79.

Each figure matches the tool’s panel. Then, at month 121, the payment jumps by $79.74, or 22.5%. Those draw years also carry 44% of the lifetime interest, and the balance never moves during them.

How Much Would a $100,000 HELOC Cost per Month?

At 7.25%, the second preset gives $604.17 a month during a 10-year draw, then $790.38 for 20 years, with $162,190.24 of total interest. Raising the rate to 8.5% lifts those payments to $708.33 and $867.82.

What matters most is the payment after month 120.

What Your HELOC Payment Result Means

According to the CFPB, monthly payments are often significantly higher once you enter repayment, so the repayment figure is the one to plan around.

Federal banking regulators, in interagency guidance issued July 1, 2014, describe the switch this way: the outstanding principal is either due immediately in a balloon payment or is repaid over the remaining loan term through higher monthly payments, resulting in payment shock.

Interest-only years also add cost, because those months pay down nothing, and the bureau notes that the part of the payment that goes to interest doesn’t reduce your balance or build your equity. Changing only the two period fields on the pinned example shows the effect:

Draw + repayment	Draw payment	Repayment payment	Total interest
10 + 20 years	$354.17	$433.91	$96,638.79
5 + 25 years	$354.17	$402.61	$92,034.06
0 + 30 years	No draw period	$384.46	$88,404.43
0 + 20 years	No draw period	$433.91	$54,138.79

Source: HELOC calculator outputs (a 0-year draw shows a zero draw payment); amortizing payment method per the CFPB

Compared with amortizing the same $50,000 over 30 years from the start, the 10 interest-only years cost $8,234.36 more interest. A quote that shows only the draw-period payment describes the cheapest decade of the line, not what it costs.

Three limits apply to every result. The tool holds one rate for the whole term, while a variable line can move with its index. For adjustable-rate loans, the bureau says your payment will typically (though not always) be re-calculated based on the new interest rate and the remaining loan term.

Fees sit outside “Total paid”, and Regulation Z makes lenders state that the annual percentage rate does not include costs other than interest. The home secures the line: “If you fall behind or can’t repay the loan on schedule, you could lose your home.”

Common Mistakes When Reading a HELOC Estimate

Treating the draw-period payment as the long-run cost. It covers interest only.
Entering a teaser rate. The bureau describes an introductory or teaser rate that is unusually low for a short period, such as six months; the calculator would apply it for the whole term.
Entering the credit limit. Interest runs on the balance you carry, so the tool needs the amount drawn instead of the full line.
Guessing the repayment term. The CFPB booklet says your lender may set a schedule so that you repay the full amount, often over ten or 15 years, while its online answer says often over ten or 20 years, so read the term from your own agreement.

On a variable line, that entered rate can change long before the term ends.

How HELOC Rates Work: Index, Margin and Rate Caps

According to the CFPB, a variable interest rate generally has two parts: the index and the margin, and common indexes include the U.S. prime rate and the Constant Maturity Treasury (CMT) rate.

The margin is the extra percentage the lender adds to the index. As a result, a HELOC rate can change when its index does, on the schedule and within any caps the plan sets.

The Federal Reserve’s H.15 release dated September 25, 2026 gives a current reference point. It lists the bank prime loan rate at 7.00% on each day from September 18 to September 24, 2026. At 8.5%, the calculator’s default sits 1.50 percentage points above that figure, a gap the lender’s margin would have to cover.

Regulation Z also requires variable-rate disclosures to include the minimum periodic payment required when the maximum annual percentage rate for each payment option is in effect for a $10,000 outstanding balance, plus a historical example based on the most recent 15 years of index values. For example, entering the plan’s maximum APR shows the worst-case payment on your own balance. On the pinned example, each extra point held for the whole term moves both payments:

Rate for the whole term	Draw payment	Repayment payment	Total interest
8.5%	$354.17	$433.91	$96,638.79
9.5%	$395.83	$466.07	$109,355.74
10.5%	$437.50	$499.19	$122,305.59

Source: HELOC calculator outputs at each rate, 10-year draw and 20-year repayment

The rate sets the cost; the lender sets the ceiling on what you can draw.

How Much Can You Borrow With a HELOC?

Lenders usually cap a HELOC at a percentage of the appraised value of your home, minus the amount you owe on your mortgage, according to the CFPB’s comparison table.

In formula terms, the limit equals the appraised value times the percentage in the lender’s terms (a maximum combined loan-to-value ratio, or CLTV), less the mortgage balance. The calculator doesn’t estimate the limit, so enter the amount you expect to draw.

Even so, the limit can shrink after approval. If the value of your home decreases significantly, your lender might decide not to allow you to take out additional credit under your HELOC plan, the bureau warns. It adds that the lender might also freeze further draws if your financial circumstances change and the lender does not believe you will be able to make your payments.

Meanwhile, lenders have kept extending lines. The Federal Reserve Bank of New York reports that HELOC limits rose by $19 billion in the second quarter of 2026, while HELOC balances rose by $13 billion totaling $459 billion, $142 billion above the low reached in Q1 2022. That balance is a small slice of the breakdown of US household debt by category, where mortgages dominate.

A fixed-rate home equity loan borrows against the same equity on different terms.

HELOC vs Home Equity Loan Payments

A home equity loan charges a fixed rate with equal payments that pay off the entire loan, according to the CFPB’s comparison table, while a HELOC typically carries a variable rate and lets you keep borrowing for several years.

The trade-off for the loan is flexibility: if you need more money, you need to apply for a new loan. Setting “Draw period” to 0 turns it into a home equity loan calculator. In other words, the draw-period payment drops to zero, and “Monthly payment during repayment” gives one level payment over the repayment years at a single rate.

Unsecured borrowing leaves the home out of it. According to the same table, a credit card carries a higher interest rate than a loan that uses your home as collateral, a gap visible in the APRs high-debt households report on their credit cards.

The same table lists an option for homeowners age 62 or older, the home equity conversion mortgage, where you don’t make monthly loan payments; the reverse mortgage market statistics show how that product has grown.

What’s the Payment on a $150,000 Home Equity Loan?

At 8.5% over 20 years, a $150,000 installment loan costs $1,301.73 a month, with $162,416.36 of total interest. Enter that balance and rate with “Draw period” at 0 and “Repayment period” at 20 to reproduce it, then change the term to compare.

What Is the Downside of a HELOC?

A HELOC’s main downside is a payment that can rise twice, and an interest-only HELOC delays the larger one. HELOCs usually have a variable interest rate, so your payments may change from month to month.

The end of the draw also adds principal to every payment. The interagency guidance also warns that some borrowers, however, may have difficulty meeting higher payments resulting from principal amortization or interest rate reset.

By contrast, some plans skip a repayment schedule entirely, and you may have to pay the entire balance owed, all at once, which might be a large amount called a balloon payment. Costs beyond interest, a line the lender can freeze and a loan secured by your home complete the list.

Is there anything else my agent or I should know about this page?

Yes. The calculator runs in your browser and nothing you enter reaches our server. It assumes the whole amount is drawn at the start, one fixed rate for the life of the line, interest-only payments during the draw period and a fully amortizing payment over the repayment period.

The draw payment is a month of interest on the balance, and the repayment payment is the standard amortization formula at the same rate. Four things sit outside the tool: a variable rate that moves with its index, rate caps, further draws or early repayments, and closing costs or annual fees.

CoinLaw publishes this page for information and gives no financial advice; the lender’s agreement and disclosures govern the actual payments.

Conclusion

At $50,000 and 8.5%, the HELOC calculator shows $354.17 a month during the draw and $433.91 once repayment begins, with $96,638.79 of total interest. Homeowners comparing offers can enter each lender’s rate and periods, check the payment example in each disclosure, and set “Draw period” to 0 to see the installment-loan alternative.

Rates and fees also differ by location; the states where home equity loans cost the most show how wide that spread runs. On a variable line, the next move in the index, such as the prime rate the Federal Reserve publishes, is the figure to watch, because it resets the payment the calculator holds fixed.