Home Equity Line of Credit Rates Comparison

This calculator compares the estimated monthly interest cost of two home equity line of credit (HELOC) rates on the same outstanding balance; enter the balance and each annual rate to see each estimate and the difference. It does not retrieve or compare live lender offers: use rate quotes and terms from the lenders you are evaluating.

Formula

For a simple monthly estimate, multiply the outstanding balance by the annual percentage rate and divide by 12, then divide by 100 to convert the percentage to a decimal:

Estimated monthly interest = balance × APR ÷ 1,200

• Balance (bal): the amount currently drawn from the line, in dollars.
• APR (rate1 or rate2): the annual rate entered as a percentage, not a decimal; for example, enter 8 for 8%.
• Monthly interest: a dollar estimate based on that balance and rate.
• Difference: rate A’s estimated interest minus rate B’s. A positive result means the estimate for A is higher; a negative result means B is higher.

The calculation treats the quoted annual rate as a simple annual rate divided evenly across 12 months. It estimates interest only, not a required payment or the total cost of borrowing. Actual interest can depend on a lender’s daily-balance method, the number of days in a billing period, rate changes, and the account’s terms.

Worked Example

Using the calculator’s defaults, the outstanding balance is $50,000, rate A is 8% APR, and rate B is 7.5% APR.

1. Rate A: $50,000 × 8 ÷ 1,200 = $333.33 estimated monthly interest.
2. Rate B: $50,000 × 7.5 ÷ 1,200 = $312.50 estimated monthly interest.
3. Difference: $333.33 − $312.50 = $20.83 per month, with A higher in this example.

The displayed amounts are rounded to cents. This example is arithmetic only; it is not a statement about available offers or what a borrower may qualify for.

Assumptions

• The entered APR is treated as fixed for this one-month estimate. Many HELOCs have variable rates, so actual rates and costs can change according to the account terms.
• The calculation assumes a constant balance throughout a 12-month year and estimates one month as one-twelfth of annual interest.
• It does not model daily compounding, payment timing, rate changes, fees, taxes, insurance, or other charges.
• The estimate is interest only. It does not calculate principal repayment, a minimum payment, a draw-period payment, or a repayment-period payment.

How to Compare HELOC Rate Quotes

A rate comparison is meaningful only when the figures refer to comparable borrowing and timing. Check whether each quote is an introductory rate, a current variable rate, or a rate that applies after a specified period. For a variable line, ask how the rate is determined, how often it can change, and whether the lender’s disclosure describes any caps or floors. These are terms to verify in the specific offer, not details this calculator can infer.

Also confirm whether a quoted figure is an APR and what charges it includes. A rate alone cannot show the full cost of opening or maintaining a line. The lender’s written disclosure is the source for its fees, payment rules, rate-adjustment terms, and any conditions attached to a quote. This page does not estimate those charges or rank lenders.

• Enter the same outstanding balance for both rates to isolate the effect of the rate.
• Compare quotes for the same point in time and the same type of rate period.
• Review the terms for rate adjustments, fees, draw and repayment periods, and required payments.
• If balances may change, repeat the estimate at several plausible balances rather than assuming today’s balance applies throughout.

What the Estimate Does—and Does Not—Tell You

The result shows how different APR inputs affect a simple interest estimate at one balance. For example, a half-percentage-point gap produces a different dollar difference on a $10,000 balance than on a $100,000 balance. The gap does not establish the total amount paid over a year because a HELOC balance can rise or fall, and a variable rate can change. The calculator also does not account for principal payments.

A HELOC is a revolving credit line secured by home equity. The borrower can generally draw funds up to the available credit under the agreement, and interest is charged on amounts borrowed rather than the full credit limit. The property secures the debt, so missed payments can have serious consequences, including risk to the home. A credit limit is not the same thing as an outstanding balance.

One common misconception is that a lower quoted rate necessarily means a lower overall cost. The rate is important, but fees, introductory periods, rate changes, balance patterns, and repayment requirements can also affect costs. A rate comparison is one input to understanding an offer, not a complete comparison of loan terms.

Common Comparison Problems

Be careful not to compare an introductory rate with a later variable rate as though both applied for the same duration. Nor should a promotional figure be assumed to last for the life of the line unless the lender’s disclosure says so. If the lender quotes a range or a rate subject to change, the calculator cannot select the applicable figure; enter a specific rate from the written offer and label the result accordingly.

Another source of confusion is APR versus the periodic rate. The calculator expects an annual percentage: enter 8 for 8%, not 0.08 and not a monthly rate. Dividing the annual rate by 1,200 converts it to a monthly decimal for this simplified estimate. Rounding can also cause small differences from a lender’s statement, particularly when the lender calculates interest daily or uses a different number of days in the billing cycle.

Frequently Asked Questions

How do I compare HELOC interest rates?
Compare written quotes for the same rate period and use the same balance to understand the basic interest difference. Also examine rate-adjustment terms, fees, and payment requirements in each lender’s disclosure.

Is a HELOC rate fixed or variable?
It depends on the specific line and its terms. Some rates can change over time. Check the offer documents for how the rate is set and when adjustments can occur.

Does this calculator show my HELOC payment?
No. It estimates monthly interest on an entered balance. A required payment may include principal or be calculated under separate draw-period or repayment-period rules.

Why does my lender’s interest figure differ from this estimate?
The lender may calculate interest using daily balances, actual days in the billing period, changing balances, rate adjustments, or account-specific rules. This calculator uses a simplified monthly estimate.

Does the HELOC interest apply to my full credit limit?
The estimate uses the outstanding balance you enter, not the available credit limit. Check the account terms for how interest and payments are calculated on amounts drawn.

Can the lower rate still cost more overall?
It can be possible when other terms differ, such as fees, the duration of an introductory rate, later rate changes, or the amount and timing of borrowing. The calculator compares interest at one balance and does not evaluate total costs.

This result is an estimate for education, and the lender’s disclosure gives the exact figures.

Related

• Home Equity Line of Credit Interest Accrual Explained
• Home Equity Line of Credit: How It Works
• HELOC Calculator: Estimate Payments and Interest

in bal | Outstanding balance | $ | 50000 | 0 | 100000000
in rate1 | HELOC rate A (APR) | % | 8 | 0.01 | 100
in rate2 | HELOC rate B (APR) | % | 7.5 | 0.01 | 100
out cost1 | Monthly interest at rate A | $ | bal * rate1 / 1200 | 2
out cost2 | Monthly interest at rate B | $ | bal * rate2 / 1200 | 2
out diff | Monthly difference (A minus B) | $ | cost1 - cost2 | 2