Calculation details
Planning estimate only, not financial, tax, or legal advice. Verify assumptions and current rules before making decisions.
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Use this result
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What does this calculator estimate?
A HELOC calculator shows your monthly payments across a home equity line of credit: an interest-only amount during the draw period and the full amortizing payment once repayment begins. Enter the amount, rate, term, and draw years to see both.
- Draw period: interest-only payments
- Repayment: balance amortizes over remaining term
- Payment = balance × r ÷ (1 − (1+r)^−n)
How a HELOC works
A home equity line of credit lets you borrow against your home's equity up to a limit. During the draw period (often 5–10 years) you typically pay interest only; after it ends, the balance must be repaid, so the payment jumps to a full amortizing amount.
Limitations to watch for
Most HELOCs have variable rates that reset with an index, so payments can rise. The amortizing payment assumes a fixed rate for the repayment phase — your actual rate can change. Interest deductibility on home-equity debt was restricted by the 2017 tax law; confirm your situation.
How to use it in practice
Plan for the payment jump before the draw period ends — the amortizing payment can be 2–3× the interest-only amount. Borrow only what you need and understand the rate floor/ceiling. Because your home secures the debt, default risks foreclosure.
["Enter the amount you'll draw.", 'Enter the rate, total term, and draw-period length.', 'The tool returns the interest-only and amortizing payments.']
How this calculator works
Formula
Interest-only payment = balance × monthly rate (APR ÷ 12). Amortizing payment = balance × r ÷ (1 − (1 + r)^−n), where r is the monthly rate and n the months remaining after the draw period.
Worked example
A $50,000 HELOC at 8% with a 10-year term and 5-year draw: interest-only payment = $50,000 × 0.006667 ≈ $333.33/month. After the draw, the balance amortizes over 60 months at about $1,013.82/month.
Assumptions to verify
- The rate stays constant at the entered APR.
- During the draw you pay interest only, with no principal reduction.
- Repayment uses a fixed-rate amortization over the remaining months.
Frequently asked questions
What is a HELOC?
A home equity line of credit is a revolving credit line secured by your home. You draw what you need during the draw period, then repay over the remaining term.
How is a HELOC different from a home equity loan?
A home equity loan is a lump sum with fixed payments; a HELOC is a revolving line you draw as needed, usually with variable rates and interest-only payments during the draw.
Why does the payment jump?
During the draw period you pay interest only. When repayment begins, you must also repay principal, so the monthly payment rises significantly.
Are HELOC rates fixed or variable?
Most are variable — they track an index (like the prime rate) plus a margin. Your rate and payment can rise when rates rise.
Is HELOC interest tax deductible?
Under current rules, interest is deductible only if the loan is used to buy, build, or substantially improve the home. Confirm with a tax professional for your situation.
What is loan-to-value and why does it matter?
LTV = loan balance ÷ home value. Lenders typically cap your combined LTV (mortgage + HELOC) at 80–90%, so your available credit depends on your home's value and existing mortgage.
What happens if I can't repay?
The HELOC is secured by your home, so defaulting can lead to foreclosure. Only borrow against equity you can confidently repay.
Cite this tool
BoringToolsKit. “HELOC Calculator.” boringtoolskit.com/heloc-calculator/ (reviewed 2026-08-25). Free to reference in articles, syllabi, and answer posts with a link.
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