How a HELOC actually works

A home equity line of credit, or HELOC, is a revolving loan secured by the borrower's interest in a home. A lender sets a line, and the borrower draws only the amount needed. Repaying principal restores room during the draw period, subject to the agreement.

That makes a HELOC different from a lump sum home equity loan. A lump sum loan advances its full principal at closing. A HELOC begins as available credit and becomes debt only as draws create a balance. How home equity works explains the residual value behind the security. The home equity against LTV comparison shows the same property split as dollars and as a ratio.

The home is collateral for the line. That legal claim is why a HELOC is secured credit rather than ordinary revolving card debt. The contract controls the line, the draw window, rate rule, fees and repayment schedule.

Many HELOCs require only accrued interest during the draw period. For a balance $B$ and annual rate $r$, the monthly amount is

$$I_m = \frac{B \times r}{12}$$

At $50,000 and 8 percent, the annual interest is $4,000 and one twelfth is $333.33 after rounding. At $20,000 and the same rate, annual interest is $1,600 and the monthly amount is $133.33.

Interest only describes the required calculation, not a falling balance. If the borrower pays only the interest and makes no new draw, the principal is still $50,000 or $20,000 at the end of the month. Principal is the amount still owed before the next interest charge.

The calculator above can show the payment on an amortising loan. During the interest only draw period, the simpler balance times rate calculation owns the result.

The draw period is the revolving phase. The borrower can take funds, repay them and draw again while the agreement permits. Each statement's interest follows the balance and rate for that billing period. A larger draw raises the next charge. A principal repayment lowers it.

The repayment period changes the contract's job. New draws stop, the outstanding balance is placed on a repayment schedule, and each required payment includes interest plus principal. The loan payment calculator applies that amortising formula once the remaining balance, rate and term are known.

A small required payment during the draw period therefore does not imply the same payment after the draw period. The first pays for use of the money. The second also returns the money over the remaining term.

A typical HELOC rate is an index plus a lender margin. When the index resets, the annual rate can move even if the balance is unchanged. The interest only formula then uses the new rate for the applicable period.

This creates two moving parts. Draws and repayments move the balance. Rate resets move the price charged on that balance. Holding one still makes the other visible, which is why both worked examples keep the annual rate at 8 percent and change only the balance.

An agreement can also set a minimum rate, a maximum rate, or limits on how quickly the rate changes. Those terms govern the actual statement. How mortgages work explains the fixed principal and scheduled payment structure that a first mortgage usually follows.

Home equity is current value minus debt secured on the home. A lender does not necessarily make all of that residual available. It can apply a combined loan to value ceiling, review income and credit, and subtract the first mortgage before setting a HELOC line.

The approved line is also not the outstanding balance. The line is the maximum revolving facility. The balance is what has actually been drawn. Interest is charged on the balance under the agreement, not automatically on every unit of unused room.

A HELOC can place the home at risk because the line is secured. Comparing a draw with an ordinary mortgage therefore requires more than comparing the first monthly charge.

The worked figures isolate an interest only month: $50,000 at 8 percent gives $333.33 monthly and $4,000 annually, while $20,000 gives $133.33 monthly and $1,600 annually. Actual statements can accrue interest by daily balance and day count, so the contract translates the annual rate into the billed period.

The decision to open or draw a line depends on repayment capacity, rate risk and the purpose of the borrowing. This is educational material, not financial advice.