HELOC Calculator

A HELOC opens with a draw period, usually ten years, and during that stretch the line works like a credit card secured by your house. You borrow when you need to, repay when you can, and borrow again. The required payment covers interest only, calculated on whatever you have actually drawn. Pull $30,000 of a $150,000 limit and you pay interest on the $30,000, not the limit. The comfort of that minimum payment is the trap. Interest-only payments never reduce principal, so a borrower who pays the minimum for ten years still owes every dollar drawn on the day repayment starts. Nothing stops you from paying more. Extra payments go straight to principal, cut the next month's interest charge, and, unlike a home equity loan, stay available to borrow again if a new expense turns up. Borrowers who pay principal anyway through the draw years come out of the decade in far better shape than the ones who let the balance sit.

Take the calculator's default scenario: $80,000 drawn at 8.5%. The interest-only payment is about $567 a month. When the draw period closes, that $80,000 starts amortizing over the repayment term. The payment becomes roughly $694 on a 20-year schedule, $788 on 15 years, and $992 on 10 years. The shortest schedule raises your monthly cost by about three quarters over what you had been paying. You have more options before that deadline than after it. Some borrowers refinance the balance into a fixed-rate home equity loan a year or so before repayment begins and lock a level payment. Some make steady principal payments through the draw years so less remains to amortize. A few lenders will extend the draw period or convert the balance to a fixed payoff plan, but only if you ask before the reset date. The weakest position is learning the new payment when the first bill shows up.

Your HELOC rate is the prime rate plus a margin. Prime tracks the federal funds rate, so Federal Reserve policy reaches your statement within a billing cycle or two. Between March 2022 and July 2023 the Fed raised its target by 5.25 percentage points, and a borrower who opened a line at 4.5% in early 2022 was paying close to 9.75% eighteen months later. On an $80,000 balance that added about $350 a month. Even a milder 2% move adds $133. Two parts of the contract limit the damage. Most lines carry a lifetime cap, commonly 18%, and some add periodic caps on each adjustment. The margin is the part you can influence: it is set at origination, never changes afterward, and lenders will sometimes shave it for strong credit, low CLTV, or an existing banking relationship. Index, margin, and cap structure vary between lenders far more than the advertised teaser rate does, so compare those terms, not the headline number. Before you sign anything, test your budget at a rate two or three points above today's. If the payment at that level would hurt, draw less than the lender offers.

The two products borrow against the same equity and put the same house up as collateral, but they behave differently enough that most borrowers are clearly better served by one or the other. A home equity loan hands you the full amount at closing at a fixed rate, and the payment never moves. That fits a single known expense: a roof quote, a consolidation with a fixed target, one tuition bill. A HELOC fits spending that arrives in stages, like a renovation that runs across a year, because you draw as invoices come due and pay interest only on what is actually out. Cost structures differ too. Home equity loans usually price a touch below a HELOC's starting rate and stay put, while the HELOC floats with prime for as long as it stays open. If you cannot predict the amount or the timing, take the line. If you know both, take the loan and the certainty that comes with it.