HELOC Calculator

Why do HELOC payments increase so much after the draw period?

During the draw period, most HELOCs allow interest-only payments. This means your monthly payment covers only the interest charged during that billing cycle, while the principal balance usually stays the same unless you make extra payments.

When the draw period ends, the HELOC enters the repayment period. At that point:

• new withdrawals are no longer allowed

• the remaining balance must be repaid

• payments must cover both principal and interest

Because the remaining balance now has to be repaid over a fixed number of years, the monthly payment can increase significantly compared to the earlier interest-only payment. For example:

• Draw period payment: interest only on $80,000 at 7% ≈ $467/month

• Repayment period payment (15-year amortization): ≈ $719/month

This calculator models both phases so you can see how the payment changes when the repayment period begins.

How is HELOC interest calculated exactly?

HELOC interest usually accrues daily based on the outstanding balance. To ensure precise results, this calculator performs all calculations using cent-level rounding similar to how banks post interest on statements. Interest is added to the balance at the end of each billing cycle before the payment is applied.

What happens when the HELOC draw period ends?

During the draw period, you can withdraw funds from the credit line and usually make interest-only payments. When the draw period ends, the HELOC enters the repayment period. At that point:

• no new withdrawals are allowed

• the remaining balance converts to an amortizing loan

• payments increase because they now include both principal and interest

Can I model rate changes?

Yes. You can add a Rate Change transaction with the date the new interest rate takes effect. The calculator applies:

• the previous rate up to that date, and

• the new rate from that date forward

This allows you to simulate variable-rate HELOC scenarios.

How are HELOC payments applied?

Payments are applied using the standard banking order:

1. Accrued interest is paid first

2. Remaining payment reduces the principal balance

At the end of each billing cycle, accrued interest is added to the balance. The payment is then applied so the statement reflects the correct outstanding balance.

What is available credit on a HELOC?

Available credit represents how much you can still borrow from your line of credit. It is calculated as:

Available Credit = (Home Value × Maximum LTV%) − Mortgage Balance − HELOC Balance

If the result becomes negative (for example if property values fall), the calculator caps the available credit at $0 and displays a warning.

Can I pay off a HELOC early?

Yes. Most HELOCs allow early repayment without penalty. You can model additional payments by entering payment transactions in future months. The schedule will update automatically and show:

• the new payoff date

• the reduced interest cost

• the savings compared with the standard repayment schedule.

Why use 365 days instead of 360?

Most consumer HELOCs in the United States calculate interest using an Actual/365 day-count convention, meaning the daily rate is APR ÷ 365. Some lenders instead use a 360-day convention, where the daily rate becomes: APR ÷ 360. Because the denominator is smaller, the daily rate is slightly higher under the 360-day method.

Your loan agreement will specify which method your lender uses. This calculator defaults to 365 days, which is the most common convention for consumer HELOCs.

What is the difference between a HELOC and a home equity loan?

A HELOC (Home Equity Line of Credit) works like a revolving credit line secured by your home. You can borrow, repay, and borrow again during the draw period.

A home equity loan is a traditional installment loan. You receive a lump sum upfront and repay it with fixed monthly payments over a set term.

HELOCs usually have variable interest rates, while home equity loans often have fixed rates.

Is HELOC interest tax deductible?

In the United States, HELOC interest may be tax deductible if the borrowed funds are used to buy, build, or substantially improve the home securing the loan. Interest used for other purposes (such as paying off credit cards or funding personal expenses) may not qualify.

Tax rules can change and depend on your personal situation, so consult a qualified tax professional for guidance.