Home equity line of credit (HELOC): How it works

Written by Samantha SheltonNMLS 1647301Updated September 2026

A home equity line of credit is a revolving line of credit secured by your home: you borrow against your equity as you need it, pay it back, and borrow again, much the way a credit card works. The Consumer Financial Protection Bureau spells out the standard sizing math in its own HELOC booklet, a lender takes a percentage of the appraised value, say 75 percent, then subtracts the balance owed on the existing mortgage, so a $100,000 home with $40,000 still owed supports a $35,000 line.

A HELOC then runs in two phases. During the draw period, commonly about 10 years, you can borrow repeatedly and often pay interest only. When that window closes, borrowing stops and the balance converts to a repayment period of roughly 10 – 20 years at principal plus interest. Rates are usually variable, quoted as a published index plus a margin, and federal law requires every variable-rate plan secured by a dwelling to carry a ceiling on how high that rate can climb over the life of the plan.

Learn how a home equity line of credit works, including how lenders size your credit limit, what happens the day the draw period ends, and how a HELOC stacks up against the two other ways to tap equity. If you’re weighing all of them, our Home Equity guide and the broader Refinancing and Home Equity hub map the whole territory.

Key takeaways:

• Two phases, two different payments: The draw period commonly runs about 10 years with interest-only payments allowed, then the repayment period runs 10 – 20 years and requires principal plus interest, so your payment steps up on the conversion date.
• Your equity sets the limit: The CFPB’s worked example uses 75% of appraised value minus the mortgage balance, while lenders in Align’s network more often cap combined borrowing at 80% – 85%, on a $400,000 home with a $250,000 mortgage, that’s the difference between a $70,000 line and a $90,000 line.
• You get 3 business days to walk away: Because a HELOC on your principal home puts the house at risk, the Truth in Lending Act lets you cancel in writing within three business days of opening the account, and the lender must then release its security interest and return every fee you paid to open it, including the appraisal and application fees.

What is a home equity line of credit (HELOC)?

A home equity line of credit is a form of revolving credit in which your home serves as collateral, letting you draw money up to an approved limit, repay it, and draw again during a set window. That structure is what separates it from every other mortgage product: a first mortgage or a home equity loan hands you a fixed sum once, while a HELOC hands you access.

Because it sits behind the loan you used to buy the house, a HELOC is usually a second lien, one of the more common forms of second mortgage. The equity backing it is simply your home’s value minus what you owe, which is the same arithmetic behind your loan-to-value ratio. Because that value moves with the market, lenders watch it closely; the FHFA House Price Index for tracking home values is the standard public gauge, and it showed U.S. house prices up 2.1% year over year in the second quarter of 2026. Homeowners are leaning on that equity more, not less: Federal Reserve Bank of New York data put outstanding HELOC balances at $459 billion at the end of June 2026, up $13 billion in a single quarter.

How does a HELOC work?

A HELOC works in two clearly separated phases, and the transition between them is where most of the surprises live. Here’s what changes when the draw period ends.

One structural warning from the CFPB deserves its own sentence: some plans don’t amortize at all and instead demand the full outstanding balance in one balloon payment when the plan ends. Read your agreement for the words “balloon payment.” If they appear, you’ll need to refinance the balance, sell, or pay it off in cash.

A HELOC also travels on a different paperwork track. Because it’s open-end credit, it doesn’t come with a Loan Estimate or a Closing Disclosure. Federal rules instead require the lender to hand you home equity plan disclosures, the CFPB’s HELOC brochure, and a list of local housing counseling organizations at the time you get the application, and to refund your fees if a disclosed term other than the variable-rate feature changes before the plan opens and you back out because of it.

How lenders size your HELOC credit limit

Start with your home’s value, multiply by the lender’s combined loan-to-value cap, and subtract every mortgage balance already recorded against the property including any second mortgage you already carry. Say your home appraises at $400,000 and you still owe $250,000 on the first mortgage:

• At the CFPB’s illustrative 75% cap: $400,000 × 75% = $300,000, minus $250,000, leaves a $50,000 line.
• At an 80% cap: $400,000 × 80% = $320,000, minus $250,000, leaves $70,000.
• At an 85% cap: $400,000 × 85% = $340,000, minus $250,000, leaves $90,000.

Same house, same mortgage, and a $40,000 spread in what you can access, which is exactly why the lender you choose matters more on a HELOC than most borrowers expect. Lenders in Align’s network set their own combined loan-to-value ceilings, and a few go higher than 85% for strong credit profiles.

The cap is only the first gate. Lenders also underwrite your ability to repay, so your credit score and your debt-to-income ratio decide whether you get the full number the equity math produced, a smaller line, or a decline. Before you borrow against any of it, our guide to using home equity wisely is worth the ten minutes.

How HELOC interest rates work

Most HELOC rates are variable, and by law the variable rate has to be tied to a publicly available index the lender doesn’t control. The prime rate is the common choice. Your rate is that index plus a fixed margin, so when the index moves, your rate and your payment move with it. Ask for the margin in writing, because it’s the only half of the equation the lender actually sets, one of several questions worth raising early, as our home equity loan tips lay out.

Two protections come standard. Variable-rate plans secured by a dwelling must carry a lifetime cap on how far the rate can rise, and the lender must disclose the maximum rate that could apply under each payment option. Some plans add periodic caps limiting how much the rate can move at any single adjustment, and many lenders let you convert all or part of a drawn balance to a fixed rate for a term, useful once you know what you actually borrowed.

When you compare offers, look past the teaser. Introductory HELOC discounts are often unusually low for a short window such as six months, and the CFPB warns that a HELOC’s APR is based on the interest rate alone. Unlike a first mortgage’s APR, it does not fold in points, closing costs or other charges, so two lines with the same APR can cost very different amounts to open. Ask for the maximum APR the lender must disclose for each payment option, too, since that is the ceiling your payment is really measured against. The CFPB explainer on how rate and APR differ on variable-rate credit is the clearest short read on why.

HELOC vs. home equity loan vs. cash-out refinance

These are three different products, and the right one is usually decided by whether your expense is a known number or a moving target. A HELOC gives you access, a home equity loan gives you a lump sum, and a cash-out refinance replaces the mortgage you already have.

The third row is the one people skip. If your current mortgage rate sits well below today’s market, a cash-out refinance gives it up on the entire balance, not just the cash you take, which is why second liens win so often in a higher-rate market. Read home equity loans: pros and cons for the fixed-rate side of the choice, and what is a cash-out refinance loan for the full-replacement route.

What people use a HELOC for, and the tax rule that follows the money

The CFPB notes that many homeowners reserve home equity lines for major items (education, home improvements, medical bills) and keep them away from day-to-day spending. Renovation is the classic fit: the cost arrives in stages, and a line bills you only for the stages you’ve paid for.

How you spend the money also decides the tax treatment. Under current federal rules, interest on a home equity loan or line is deductible only if the borrowed funds are used to buy, build, or substantially improve the home that secures the loan, and only within the overall limit on home acquisition debt, $750,000, or $375,000 if married filing separately, for debt taken on after December 15, 2017.² Using a HELOC to consolidate credit cards or pay tuition does not qualify. The IRS rules on deducting home mortgage interest in Publication 936 lay out both tests, and our home equity loan tips cover how to document an improvement so the deduction survives review.

The risks of a HELOC

The flexibility that makes a HELOC useful is the same thing that makes it risky, and four of those risks are worth naming before you sign.

• Your payment moves without your permission: A variable rate means the monthly number changes with the index. The lifetime cap tells you the worst case, so ask what the payment looks like at that ceiling, not just at today’s rate.
• The end of the draw period is a cliff, not a ramp: On a $50,000 balance at an illustrative 8%, an interest-only payment near $333 becomes about $607 if the repayment period runs 10 years. Paying principal during the draw, or refinancing the balance before it converts, are the two ways to soften it.
• The lender can freeze or shrink your line: Plans generally permit a lender to cut off new draws or reduce the limit if the home’s value declines significantly, or if it reasonably believes a material change in your finances will keep you from paying. A HELOC opened as an emergency fund can be gone in exactly the emergency you opened it for.
• The house is the collateral, and it settles first: Miss enough payments and you can lose the home. Sell it, and you’ll almost certainly have to pay the line off in full at closing, whether or not you planned to.

None of that makes a HELOC a bad product. It makes it a product that rewards a plan, which is the whole argument in using home equity wisely.

What Michigan homeowners should know

Michigan changes the size of a HELOC decision, not its shape. The median value of owner-occupied homes in Michigan was $254,200 in the 2024 American Community Survey against $360,600 nationally, so the same combined loan-to-value cap produces a materially smaller line here than the national examples suggest.

• A smaller ceiling on a median home: At an 85% cap, a $254,200 Michigan home supports about $216,000 of total secured debt, so an owner still owing $150,000 reaches roughly $66,000 against about $156,000 on the national median with the same balance. Size the project to your ceiling, not to a national article.
• The redemption clock is six months: Under MCL 600.3240, when residential property of four units or fewer is foreclosed by advertisement and more than 66-2/3% of the original debt is still owed, the redemption period after the sheriff’s sale is six months. That is the reason to keep a drawn balance small enough that you never meet it.
• Recording a line is cheap; the wrong lender is not: A Michigan register of deeds charges a flat $30 per document, so the paperwork cost of adding a second lien is trivial next to the $40,000 spread a different combined loan-to-value cap can create. Many Michigan retail banks offer exactly one HELOC on one set of terms; because Align is a broker, we place lines through partner wholesale lenders with different caps, credit thresholds and fees, then show you where your file prices best. Our guide to using home equity wisely covers which uses hold up over a full draw-and-repayment cycle.

FAQ: Home equity lines of credit

Here are answers to common questions about home equity lines of credit.

How much can you borrow with a HELOC?

Most lenders allow total mortgage debt of about 80% to 85% of your home’s appraised value, though the CFPB’s own illustration uses 75%. On a $400,000 home with a $250,000 first mortgage, an 85% cap works out to roughly $90,000 of availability and an 80% cap to $70,000. Your credit score, income, and debt load then decide how much of that you actually get, since the line still has to fit your debt-to-income ratio.

What happens when the HELOC draw period ends?

Borrowing stops and the line converts to the repayment period, usually 10 to 20 years of principal-plus-interest payments on whatever balance remains. On a $50,000 balance at an illustrative 8%, the jump runs from about 25% if repayment is spread over 20 years to roughly 80% if it runs 10 years. Some plans instead require the entire balance as a single balloon payment, which is the version you most want to catch early, our home equity loan tips explain what to ask before you sign.

Is HELOC interest tax deductible?

It can be. Under current federal rules, interest on home equity debt is deductible only when the proceeds buy, build, or substantially improve the home securing the loan, and only within the overall mortgage interest limits. Consolidating credit cards or paying tuition with a HELOC does not qualify. Confirm your own situation with a tax professional, and see using home equity wisely for how the use test shapes the decision.

What is the difference between a HELOC and a home equity loan?

A home equity loan hands you a lump sum at a fixed rate with a fixed payment from day one. A HELOC gives you a revolving line you draw from as needed, usually at a variable rate, with interest charged only on what you’ve actually taken. Choose the loan for a one-time known expense and the line for ongoing or uncertain costs; home equity loans: pros and cons works through both sides.

The bottom line on HELOCs

A home equity line of credit is revolving credit secured by your home, sized by taking a percentage of the appraised value (75% in the CFPB’s example, 80% to 85% at most lenders) and subtracting what you still owe. It runs a draw period of about 10 years with interest-only payments typically allowed, then converts to a 10- to 20-year repayment period at principal plus interest. The rate is usually variable with a legally required lifetime ceiling, the interest is deductible only when the money improves the home, and you have three business days after opening to cancel and get your fees back.

If you’re ready to find out whether a line, a lump sum, or a cash-out refinance actually costs you less, talk to Align Lending. We’ll shop your scenario across our lender network and put all three sets of numbers in front of you side by side. Call 248-506-5727 or start online today.

Footnotes:

1. Example figures in this article are hypothetical and for educational purposes only; they do not constitute an advertisement of credit terms or a rate quote under federal or state lending laws. The 8% rate is used only to illustrate how an interest-only payment compares with an amortizing payment on the same balance and is not a current or offered rate. Your credit limit, rate, margin, index, caps, and payment will depend on your application, your property, and market conditions. Return to text.

2. This is general information, not tax advice. Deductibility depends on how you use the loan proceeds, on your total home acquisition debt, and on whether you itemize. Consult a qualified tax professional about your situation. Return to text.

Sources: HELOC defined as revolving credit with the home as collateral; credit limits commonly set by taking a percentage such as 75 percent of appraised value less the existing mortgage balance ($100,000 value, $40,000 owed, $35,000 line); draw period such as 10 years and repayment period such as 10 years; balloon payment at the end of some plans; variable rates based on a publicly available index plus a margin; the legal requirement that variable-rate plans secured by a dwelling carry a lifetime rate ceiling; introductory discount rates; the annual percentage rate on a home equity line being based on the periodic interest rate alone and therefore excluding points, closing costs and other charges; fixed-rate conversion options; freezing or reducing a line after a significant decline in home value or a material change in the borrower’s financial circumstances; payoff in full on sale; disclosures and the home equity brochure delivered with the application; the housing counseling organization list; the refund of fees when a disclosed term changes before the plan opens; and the three-day right to cancel a line secured by a principal dwelling with all fees returned. Consumer Financial Protection Bureau, “What you should know about home equity lines of credit,” and 12 CFR § 1026.40. Three-business-day rescission period running from the later of the account opening, delivery of the rescission notice, or delivery of all material disclosures, 12 CFR § 1026.15(a)(3). Loan Estimate and Closing Disclosure required only for closed-end consumer credit secured by real property, which excludes open-end home equity plans, 12 CFR § 1026.19(e) and (f). Disclosure of the maximum annual percentage rate under each payment option, 12 CFR § 1026.40(d)(12)(ix). Home equity interest deductible only when proceeds buy, build, or substantially improve the home securing the loan, and the $750,000 / $375,000 home acquisition debt limits for debt incurred after December 15, 2017, IRS Publication 936. Conventional cash-out refinance requiring at least one borrower on title for six months before disbursement and the existing first mortgage to be at least 12 months old, Fannie Mae Selling Guide B2-1.3-03. HELOC balances of $459 billion at the end of June 2026, up $13 billion in the quarter, Federal Reserve Bank of New York Household Debt and Credit Report, second quarter 2026. U.S. house prices up 2.1 percent between the second quarter of 2025 and the second quarter of 2026, Federal Housing Finance Agency House Price Index. Median value of owner-occupied housing units of $254,200 in Michigan and $360,600 nationally, U.S. Census Bureau, American Community Survey 2024 one-year estimates, Table B25077. Six-month redemption period after a foreclosure sale of residential property of four units or fewer when more than 66-2/3% of the original indebtedness remains due, MCL 600.3240(8). Register of deeds recording fee of $30 per document regardless of page count, MCL 600.2567. Combined loan-to-value ceilings of 80% – 85% reflect terms observed among wholesale lenders in Align Lending’s network and are set by those lenders, not by Align.

This article is for informational purposes only and is not intended to provide legal, financial, or tax advice. HELOC terms, credit limits, indexes, margins, caps, fees, and combined loan-to-value ceilings are set by individual lenders and change frequently; confirm your figures with the disclosures your lender provides and consult a qualified professional about your situation. Figures shown are illustrative, are not a rate quote or an offer of credit, and are subject to change. Align Lending is an independent Michigan mortgage broker, NMLS #2041154.

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