HELOC Payment Calculator (Home Equity Line of Credit)
Estimate interest-only and amortizing payments on a Home Equity Line of Credit.
What this calculates
A HELOC has two phases: a 5-10 year draw period (interest-only on what you've used) and a 10-20 year repayment period (principal + interest). Variable rates tied to Prime mean payments rise when rates rise. This calculator shows both phase payments side-by-side.
Formula & how it works
Draw phase: interest-only = balance × (rate/12). Repayment phase: standard amortization = balance × (r/12) / (1 − (1 + r/12)^(−n)).
Worked example
$50,000 balance at 8.5% APR. Draw period interest-only: $354/mo. 15-yr repayment: $492/mo.
Frequently asked questions
How is the rate set?
Usually Prime + margin (e.g., Prime + 1%). When the Fed moves Prime, your payment changes.
Payment shock?
End of draw period can double or triple payments. Plan for it — refinance the HELOC or pay down principal before it hits.
Tax deductible?
US: interest is deductible only if used for home improvements (post-TCJA). Otherwise no longer deductible.
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