HELOC & Home Equity Loan Calculator
Calculate maximum HELOC borrowing limit based on home value × LTV ratio − current mortgage. Compare interest-only payments during draw vs amortising payments during repayment.
HELOC Calculator
Your home & current mortgage
HELOC terms
Monthly payment by phase (drawing —)
Lifetime cost — draw period vs repayment period
How to use the HELOC Calculator
Enter your home value and current mortgage
Home value should be the realistic current market value — your last appraisal, a recent comparable sale on your street, or a Zillow/Redfin estimate. Current mortgage is the remaining balance you owe, not the original loan amount. The gap between the two is your raw equity — but lenders only let you borrow against a portion of it.
Pick the lender LTV cap
Loan-to-Value cap is the maximum total mortgage debt the lender will allow as a percentage of home value, counting the first mortgage and the HELOC together. Caps of 80–85% combined LTV are common in US bank underwriting; some credit unions and specialty lenders go higher. The cap is the lender's policy, not a statutory figure — read it off the lender's disclosure. The lower the cap, the smaller your HELOC. The math: max HELOC = (home value × LTV cap) − current mortgage balance.
Set HELOC rate, draw and repayment periods
HELOC rates are typically variable: an index — most often the US prime rate, 6.75% on the Federal Reserve's H.15 release of 11 September 2026 — plus a lender margin (CFPB, What You Should Know About Home Equity Lines of Credit). A draw period of about 10 years with interest-only minimum payments is a common shape; the CFPB notes that repayment schedules "often" run ten or 15 years, and that some plans instead demand the whole balance at once as a balloon payment. The 10 + 20 defaults here are one common structure — set them to match your own disclosure.
Compare the payment shock between phases
The interest-only payment during draw is small and seductive — borrowers often forget the payment will jump dramatically when repayment kicks in. A $100K HELOC at 8.5% costs $708/month interest-only, then jumps to $868/month amortising over 20 years. Plan for the shock or pay down principal voluntarily during the draw period to ease the transition.
HELOCs — borrowing against your house, the right way and the wrong way
A Home Equity Line of Credit (HELOC) is a revolving credit line secured by your home, similar to a credit card except backed by the value of your house instead of just your promise to pay. You can draw, repay, and re-draw during a fixed "draw period" (typically 10 years), paying interest-only on the outstanding balance. After draw ends, the credit line closes and you enter a "repayment period" (typically 20 years) where the outstanding balance amortises with principal-plus-interest payments. Unlike a cash-out refinance, a HELOC is a second mortgage — your first mortgage stays untouched. This makes HELOCs especially attractive when your existing mortgage is at a much lower rate than current refinance rates would be (the position of US homeowners who locked in sub-3% mortgages around January 2021, when Freddie Mac's 30-year average hit a record low of 2.65%).
The LTV math that determines your borrowing limit
Lenders cap the combined Loan-to-Value (CLTV) — your first mortgage plus the HELOC — as a percentage of home value. Combined-LTV caps of 80–85% are common at US banks; some credit unions and specialty lenders go higher, and the cap is lender policy rather than regulation. A home worth $600K with a $350K first mortgage and an 85% CLTV cap means total allowable debt is $510K, leaving $160K of available HELOC. The lower the cap, the safer the loan for the lender — and the smaller your line. Lenders generally price a lower-CLTV line below a higher one, because the equity cushion protecting them is larger. If you don't need the maximum, taking less line at a lower LTV usually saves money long-term.
The other gotcha: lenders re-evaluate home value during the draw period. In a sharp housing downturn — as happened to many homeowners in 2008-2010 — lenders can "freeze" or even reduce your unused credit line if they think your equity cushion has eroded. Regulation Z (12 CFR §1026.40(f)(3)(vi)) expressly permits this when the home's value "declines significantly below the dwelling's appraised value", or when the lender reasonably believes you can no longer meet the payments — and lenders used that clause widely in 2008–2009, including on lines that had never been tapped. The credit line is a promise, not a guarantee — and a downturn can break the promise at the worst possible time.
The ASEAN angle — equity loans look different in APAC
HELOCs in the strict US sense aren't widely offered across Singapore, Malaysia, Indonesia, the Philippines, Thailand, or Vietnam. Most APAC banks instead offer "term loans secured by property" or "home equity loans" — closed-end second mortgages with fixed terms and lump-sum disbursement, not the revolving credit line model. Singapore's DBS, OCBC, and UOB all offer "Home Equity Loans" or "Property Term Loans" but not draw-and-repay revolving HELOCs. For retirees, the closest equivalent is the HDB Lease Buyback Scheme or private-bank reverse mortgages, which let elderly owners monetise home equity for retirement income. Malaysia's banks offer term loans secured by property, but again — fixed disbursement, not a revolving line. Indonesia's KPR (Kredit Pemilikan Rumah) ecosystem is mortgage-first; equity extraction is unusual. The takeaway for APAC homeowners: if you want HELOC-style borrowing flexibility, you typically need to apply for an overdraft secured by your property, which exists at most major regional banks but with paperwork and fees comparable to a refinance.
A HELOC is a credit card backed by your house. Used for high-ROI purposes — home improvement, education, debt consolidation — it's one of the cheapest sources of long-term capital. Used carelessly, it's the fastest path to losing your home.
When HELOC beats cash-out refinance — and when it doesn't
HELOC wins when your existing mortgage rate is significantly lower than current refinance rates. If you locked a 3% mortgage in 2021 and current rates are 7%, refinancing the full mortgage to extract equity means re-financing the whole balance at 7% — far more expensive than carrying the original mortgage and adding a smaller HELOC at 8%. The math: $400K at 3% costs $1,686/month; refinancing $500K (including $100K cash-out) at 7% costs $3,327/month — vs keeping the original mortgage ($1,686) + a $100K HELOC at 8.5% ($868/month amortising) for a combined $2,554. The HELOC route saves $773/month even at a higher HELOC rate. Cash-out refi wins when (a) you need more cash than the lender's per-line ceiling allows, (b) you want a fixed rate (HELOCs are variable), or (c) your existing mortgage rate is close to current rates anyway.
Common HELOC use cases — ranked by financial sense
Home improvement — usually the best use. Adds value back to the property securing the loan, and the interest may be tax-deductible in the US: under IRS Publication 936 (2025 returns) the loan must be used to "buy, build, or substantially improve" the home that secures it, and it counts toward the USD 750,000 acquisition-debt cap (USD 375,000 married filing separately). Debt consolidation — strong case when moving high-rate credit-card balances onto a line priced at a fraction of the card rate, but only if the borrower changes the spending behaviour that created the debt; otherwise the cards refill and the home is now collateral for the original problem. Education funding — defensible but federal student loans are often cheaper and have better deferral options. Business capital — high-risk; putting personal residence at stake for business venture is rarely the optimal capital stack. Investment portfolio leverage — controversial; some sophisticated investors do this, but margin calls during downturns mean potential forced selling at the worst time. Vacation, wedding, luxury consumption — almost never makes sense; you're borrowing against your home to pay for a depreciating experience.
The variable-rate risk most borrowers underestimate
HELOC rates are indexed — usually to the US prime rate — plus a lender margin. Prime stood at 6.75% on the Federal Reserve's H.15 release of 11 September 2026, after sitting at 8.50% from July 2023 to September 2024 and at 3.25% through 2020–21 (Federal Reserve H.15 / FRED series PRIME). Prime moves in step with the federal funds target, so a Fed decision reaches your rate within a billing cycle or two; there is no rate-lock on a variable line. A borrower who drew at prime + 1% in early 2022, when prime was 3.25%, was paying 9.50% on the same balance eighteen months later — more than double the interest cost. Build a buffer: stress-test your budget at HELOC rate +3% before drawing. Some lenders offer "fixed-rate conversion" features that let you lock a portion of the balance at a fixed rate — useful if you want predictability on a large draw.
Combined LTV, payment shock and the IRS use-of-funds rule
The "combined LTV" cap includes BOTH your first mortgage AND the HELOC. A $600K home + $350K mortgage + 85% cap = $160K available HELOC, not $250K.
HELOC rates are almost always variable, indexed to the US prime rate — 6.75% on the Federal Reserve's H.15 release of 11 Sep 2026 — plus a lender margin. Prime tracks the federal funds target, so a Fed move reaches your line within a billing cycle or two; there is no rate-lock.
Regulation Z, 12 CFR §1026.40(f)(3)(vi), lets a lender freeze or cut an unused line when the home's value "declines significantly" below its appraised value — the clause lenders invoked across 2008–2009. The line is a promise, not a guarantee.
The "payment shock" when draw ends is real. A $100K HELOC at 8.5% goes from $708/mo interest-only to $868/mo amortising — a 23% jump that surprises many borrowers.
Under IRC §163(h)(3) as amended by the 2017 Tax Cuts and Jobs Act — and made permanent by the One Big Beautiful Bill Act of July 2025 — HELOC interest is deductible only if the funds "buy, build, or substantially improve" the home securing it, within the USD 750,000 acquisition-debt cap (IRS Publication 936, 2025 returns). Not for debt consolidation or vacations.
Singapore, Malaysia, Indonesia don't offer US-style revolving HELOCs. Most APAC banks offer "term loans secured by property" — closed-end, fixed disbursement.
The CFPB's HELOC brochure lists the charges to expect: application and appraisal fees up front, an annual fee, per-draw transaction fees, and sometimes a charge for closing the line early. Lenders must disclose all of them — compare offers line by line.
US HELOC balances stood at USD 459 billion in Q2 2026 — the 17th consecutive quarterly rise and USD 142 billion above the Q1 2022 low (New York Fed, Household Debt and Credit Report, Aug 2026) — still short of the roughly USD 714 billion peak of early 2009.
Singapore retirees can use HDB's Lease Buyback Scheme to monetise home equity for retirement — a structured alternative to HELOC for elderly owners with low cash flow.
A HELOC is a lien on the home, so default can lead to foreclosure — and because a second-lien holder is paid only after the first mortgage, a lender with thin equity behind it may pursue the debt itself rather than the property.
Frequently Asked Questions
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A HELOC is a revolving credit line — you draw, repay, and re-draw during the draw period, paying interest only on the outstanding balance, usually at a variable rate. A home equity loan is a closed-end lump-sum loan disbursed at closing, with fixed monthly payments at a fixed rate. HELOCs offer flexibility; home equity loans offer predictability. Most US lenders offer both products; the right choice depends on whether you need cash incrementally (HELOC) or all at once (home equity loan).
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Maximum borrowing = (home value × lender LTV cap) − current mortgage balance. Combined-LTV caps of 80–85% are common at US banks; some lenders go higher, and the cap is their policy rather than a regulation. Example: $600K home with $350K mortgage at 85% cap → max HELOC = ($600K × 0.85) − $350K = $160K. Lenders also set a dollar ceiling per line even if your equity supports more, and underwriting looks at credit score, debt-to-income ratio and income — not just equity.
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The credit line closes — you can no longer draw new funds. Whatever balance is outstanding enters the repayment period (typically 20 years) and amortises with principal-plus-interest payments. The monthly payment jumps because you're now paying down principal, not just interest. A $100K HELOC at 8.5% goes from $708/mo interest-only to $868/mo amortising — a 23% payment shock. Plan for this in advance or pay down principal voluntarily during draw.
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HELOCs are typically indexed to the US prime rate (set by major banks off the Federal Reserve's federal funds target; 6.75% on the H.15 release of 11 Sep 2026) plus a lender margin — "the index and the margin", as the CFPB's HELOC brochure puts it. As prime moves, your rate moves within a billing cycle or two. Lenders price HELOCs variably because the draw-and-repay structure makes fixed pricing risky for them — if rates spike, they'd lose money on existing fixed-rate lines. Some lenders offer "fixed-rate conversion" features that let you lock portions of your balance at a fixed rate for predictability.
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When your existing mortgage rate is significantly lower than current refinance rates. If you locked 3% in 2021 and current refi rates are 7%, refinancing your whole $400K mortgage to extract $100K means paying 7% on the whole new $500K loan. Far cheaper to keep the 3% mortgage and add a $100K HELOC at 8.5% — the blended cost is much lower than refinancing the whole thing at 7%. With the 30-year mortgage averaging 6.76% in the week of 10 Sep 2026 (Freddie Mac PMMS), homeowners who locked in near the 2.65% record low of January 2021 have kept those loans and added lines instead — US HELOC balances have risen for 17 consecutive quarters (New York Fed, Aug 2026).
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Yes — lenders have the contractual right to suspend new draws on your HELOC if home values drop significantly, your credit deteriorates, or in extreme market conditions. Regulation Z (12 CFR §1026.40(f)(3)(vi)) permits it when the home's value declines significantly below its appraised value, when the lender reasonably believes you can no longer repay, or when you default — the clauses invoked widely in 2008–2009. The lender can't recall money you've already drawn (that becomes a regular term loan), but they can freeze the unused portion of your line. If you're relying on a HELOC as an emergency fund, this risk is real — consider drawing and parking the cash in a savings account if you expect to need it during a downturn.
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In the US, under IRC §163(h)(3) as amended by the 2017 Tax Cuts and Jobs Act and made permanent by the One Big Beautiful Bill Act of July 2025: only if the funds are used to "buy, build, or substantially improve" the home that secures the loan, only within the USD 750,000 acquisition-debt cap (USD 375,000 married filing separately), and only if you itemise deductions (IRS Publication 936, 2025 returns). Using a HELOC for debt consolidation, education, or business capital does NOT qualify. Keep documentation (receipts, contractor invoices) proving the use-of-funds if you plan to deduct. Outside the US, deductibility rules vary — consult a local tax advisor.
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Not in the US revolving-credit-line sense. Most APAC banks (DBS, OCBC, UOB in Singapore; Maybank, CIMB in Malaysia; BCA, Mandiri in Indonesia) offer "term loans secured by property" or "home equity loans" — closed-end second mortgages with lump-sum disbursement and fixed terms, not draw-and-repay revolving lines. For retirees, Singapore's HDB Lease Buyback Scheme and private-bank reverse mortgages serve similar equity-extraction goals. If you want HELOC-style flexibility in APAC, you typically need to apply for an overdraft secured by property at a major regional bank — available but with fees comparable to a refinance.
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There is no statutory minimum — each lender sets its own credit-score, debt-to-income, income-verification and appraisal requirements, and credit unions are often more flexible than banks. The CFPB's HELOC brochure advises comparing the annual percentage rate, the index and margin, the fees and the payment terms across several offers, because those terms differ far more between lenders than the equity maths does. Expect a process similar to a refinance: application, appraisal and closing costs, all disclosed up front.
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No. All calculation happens entirely in your browser via JavaScript. Open DevTools → Network and watch — there's zero outbound traffic. Home values, mortgage balances, and HELOC parameters never leave your device.
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Method & sources
How it computes
Maximum line = home value × the lender's combined loan-to-value cap − first-mortgage balance. The draw-period payment is simple monthly interest on the drawn balance (balance × annual rate ÷ 12); the repayment-period payment is the standard level-payment amortisation P·r(1+r)^n / ((1+r)^n − 1) over the repayment months, with the whole drawn balance assumed outstanding when the draw period ends.
What this tool implements
- Interest-only minimum payments during the draw period and a fully amortising schedule during the repayment period, as described in the CFPB's HELOC brochure; 10-year draw and 20-year repayment are editable defaults, not fixed conventions.
- Variable rate = index (US prime rate, Federal Reserve H.15) + lender margin; the rate entered is the combined figure and is held constant over the schedule.
- Combined LTV counts the first mortgage and the HELOC together; the cap is a lender term the user selects, not a statutory figure.
- US tax treatment described per IRC §163(h)(3) as amended by the 2017 Tax Cuts and Jobs Act and made permanent by the One Big Beautiful Bill Act (2025): interest deductible only where the proceeds buy, build or substantially improve the securing home, within the USD 750,000 / USD 375,000 (MFS) acquisition-debt cap.
Sources
- Internal Revenue Service. Publication 936, Home Mortgage Interest Deduction (for use in preparing 2025 returns). https://www.irs.gov/publications/p936
- Board of Governors of the Federal Reserve System. H.15 Selected Interest Rates — bank prime loan rate 6.75% (release of 11 September 2026). https://www.federalreserve.gov/releases/h15/
- Consumer Financial Protection Bureau. What You Should Know About Home Equity Lines of Credit (HELOC). https://files.consumerfinance.gov/f/documents/cfpb_heloc-brochure…
- 12 CFR §1026.40(f)(3)(vi) (Regulation Z) — conditions under which a creditor may prohibit further advances or reduce a home-equity credit limit. https://www.law.cornell.edu/cfr/text/12/1026.40
What can make this go out of date
- US prime rate — Federal Reserve H.15, published daily and repriced after FOMC decisions (6.75% on 11 Sep 2026); the widget quotes it in prose, the user enters the all-in rate.
- Acquisition-debt cap and use-of-funds rule — IRS Publication 936, revised annually; USD 750,000 cap made permanent by the One Big Beautiful Bill Act (July 2025).
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