Home Equity Line of Credit: Meaning and How It Works

A home equity line of credit (HELOC) is a revolving loan secured by your home, with a credit limit based partly on the equity you have built up. Instead of receiving the full amount at once, you can usually borrow, repay and borrow again during an agreed draw period; this calculator estimates a monthly payment for a fixed-rate, fully amortizing loan, not the changing payments on a typical HELOC.

Formula

The calculator treats the amount borrowed as a fixed-rate loan repaid in equal monthly payments. It does not model a revolving credit line or the variable interest rate common to HELOCs.

Monthly payment: M = round(P × r ÷ [1 − (1 + r)⁻ⁿ], 2), where r = APR ÷ 1,200 and n = years × 12. Total interest: I = (M × n) − P.

• P is the amount borrowed, in dollars.
• APR is the annual percentage rate entered as a percentage, such as 8 for 8%.
• r is the monthly interest rate as a decimal.
• n is the number of monthly payments.
• M is the monthly payment rounded to the nearest cent.
• I is estimated total interest in dollars, calculated using the rounded payment.

Worked Example

Using the calculator defaults—$20,000 borrowed, 8% APR and a five-year repayment term:

1. Convert APR to a monthly rate: 8 ÷ 1,200 = 0.0066667.
2. Convert the term to payments: 5 × 12 = 60 months.
3. Apply the payment formula: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰] = $405.53 per month, rounded to cents.
4. Calculate interest using the rounded payment: ($405.53 × 60) − $20,000 = $4,331.80.

Assumptions

• The APR remains fixed throughout the repayment term.
• Payments are equal, made monthly, and begin one month after borrowing.
• Interest is compounded monthly at APR ÷ 12.
• Fees, taxes, insurance, escrow, additional borrowing and late payments are not included.

How a HELOC Works

Home equity is the difference between a home’s market value and the outstanding balances of loans secured by it. For example, if a home is worth $350,000 and the mortgage balance is $220,000, the simple equity difference is $130,000. That is not necessarily the amount a lender will allow a homeowner to borrow: a lender may consider the home’s valuation, existing debts and other application details, and sets the actual limit.

A HELOC generally has two phases. During the draw period, the borrower can access available credit, often through repeated withdrawals up to the limit, and payments may be interest-only or include principal, depending on the contract. After the draw period, the line generally enters repayment: further draws stop and the outstanding balance is repaid under the agreement. Payment amounts can change, particularly when the rate is variable or the repayment phase begins.

Because the home secures the debt, failure to meet the contract’s repayment obligations can put the home at risk. A HELOC is therefore different from an unsecured credit card or personal loan, even though all can provide access to borrowed money.

HELOC Compared With a Home Equity Loan

A home equity loan typically provides a lump sum with a repayment schedule, while a HELOC provides access to a credit limit that can be drawn in portions. A home equity loan’s payment structure is often easier to estimate in advance when its rate and term are fixed. A HELOC offers flexibility in when and how much to draw, but its balance and payments may be less predictable.

Neither product is automatically cheaper. Compare the actual written terms, including the rate structure, fees, draw and repayment periods, payment calculation, and what happens when the rate changes. The calculator above is useful for a hypothetical fixed-rate balance repaid in equal installments; it should not be read as a quote for a HELOC.

Costs, Risks, and Common Misconceptions

Interest is only one possible cost. A HELOC agreement may include application, valuation, account, transaction or other charges; the types and amounts depend on the offer. Ask for the complete fee schedule and determine whether charges apply even if little or none of the line is used. Also check how the interest rate is set, whether it can change, how often it can adjust, and whether the agreement specifies a rate cap or other limits.

• “My equity is my available credit.” Equity is a starting point for assessing a secured loan, not a guaranteed credit limit.
• “The initial payment tells me what I will pay throughout.” A payment can change when a variable rate changes or when the draw phase ends.
• “Borrowing is harmless if I can make interest-only payments.” Interest-only payments do not reduce principal, so the balance remains and later payments may rise when repayment begins.
• “The calculator includes every charge.” It does not; it calculates principal-and-interest payments under stated assumptions only.

Before borrowing, read the agreement for payment rules, rate adjustments, fees, repayment timing and consequences of missed payments. Consider how a change in income, expenses or the home’s value could affect the ability to repay. These are general considerations, not a judgment about any individual product.

Frequently Asked Questions

What does HELOC stand for?
HELOC stands for home equity line of credit. It is a revolving credit arrangement secured by a borrower’s home.

How is a HELOC different from a mortgage?
A mortgage is generally used to finance a home purchase or refinance a home loan, while a HELOC makes a credit line available against home equity. A HELOC is typically an additional debt secured by the property; the contract determines its terms and repayment requirements.

Can you borrow and repay repeatedly with a HELOC?
Usually, the borrower can draw, repay and draw again during the draw period, subject to the credit limit and agreement. Re-borrowing may not be available once the draw period ends.

Are HELOC payments fixed?
Not necessarily. Rates may be variable, and payment rules can differ between the draw and repayment periods. Check the agreement for how the rate and required payment are calculated.

Does a HELOC calculator show my actual payment?
No. This calculator estimates equal monthly payments for a fixed-rate loan using the values entered. A real HELOC can involve changing rates, separate draw-period rules, fees and changing balances.

Use the calculator as estimate arithmetic for education, not financial advice; it does not tell you whether to borrow or what you may qualify for. The lender’s disclosure gives the exact figures.

Related

• Aven Home Equity Line of Credit: How It Works
• Apply for a Home Equity Line of Credit Online?
• 5-Year Home Equity Line of Credit Rates Explained

in p | Amount borrowed | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Repayment term | years | 5 | 0.0833 | 50
out pmt | Estimated monthly payment | $ | round(p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)), 2) | 2
out int | Estimated total interest | $ | pmt * yrs * 12 - p | 2