Home equity planning tool
HELOC Calculator: Estimate Monthly Payments
Use this HELOC calculator to estimate available home-equity credit, an interest-only draw payment, and an amortizing repayment payment. Enter your own rate and terms because lender limits, fees, and variable-rate rules differ.
Calculator
HELOC Payment Calculator
The calculator uses your entered rate and assumptions. It does not check lender eligibility or retrieve live home values.
Your estimate
Estimated interest-only payment
Example estimateWith a $50,000 balance at 8.5%, interest-only payments are about $354.17 per month during the draw period. A 20-year repayment estimate is about $433.91 per month.
How to use this HELOC calculator
Use a consistent set of assumptions when comparing a line of credit with other borrowing options.
Estimate the home value
Enter a current value and remaining mortgage balance. Their difference is the starting equity estimate before a combined-LTV limit is applied.
Set the combined LTV limit
Enter the total loan-to-value assumption to test. It includes the first mortgage and HELOC together, not the HELOC percentage alone.
Enter the balance and rate
Use the current or planned drawn amount, then enter the annual rate to model. Test several rates when the line is variable.
Compare both payment phases
Compare the interest-only draw estimate with the amortizing repayment estimate. Repayment is usually higher because it reduces principal.
What the HELOC estimate shows
The calculator separates equity capacity from the payment on the amount actually drawn.
Estimated total HELOC limit
Home value multiplied by the assumed maximum combined LTV, less the current mortgage balance.
Estimated credit still available
The estimated limit less the current HELOC balance drawn.
Interest-only draw payment
A simple monthly interest estimate on the balance entered. It does not include fees or principal reduction.
Amortizing repayment estimate
A principal-and-interest estimate if the drawn balance were repaid evenly over the selected term.
HELOC formulas used in the estimate
These formulas explain the planning math; your lender's agreement controls the actual credit limit, rate, payment rules, and fees.
Estimated credit limit
home value x maximum combined LTV - mortgage balanceA negative result becomes zero available credit. The calculation does not model appraisal rules, income review, or credit scoring.
Draw-period payment
drawn balance x annual rate / 100 / 12This is an interest-only estimate. Some plans also require principal, minimum charges, or fees during the draw period.
Repayment-period payment
P x r x (1 + r)^n / ((1 + r)^n - 1)P is the drawn balance, r is the monthly rate, and n is repayment months. At 0%, the result is principal divided by months.
Combined LTV check
(mortgage balance + HELOC balance) / home value x 100This explains capacity; it is not an approval, appraisal, or underwriting test.
Draw period vs. repayment period
A HELOC can feel inexpensive during the draw period when payments are mostly interest. The payment can change when repayment starts.
During the draw period
You may borrow and repay up to the line's limit. This page estimates interest-only payment on the current balance, but the agreement may require principal or use another minimum-payment formula.
When repayment begins
New draws may stop and the balance may be amortized. The second result estimates an even principal-and-interest payment over your selected term.
Why the payment changes
Repayment includes principal reduction and may use a different rate. If the rate rises, the real payment or payoff time can exceed this snapshot.
HELOC payment examples
Apply a scenario to the calculator to see how the same formula responds to different home values, balances, rates, and terms.
Typical planning example
A $400,000 home, $240,000 mortgage, 80% combined LTV limit, $50,000 draw, and 8.5% rate. The draw estimate is about $354 per month before fees.
Lower-rate comparison
A $550,000 home, $300,000 mortgage, $75,000 draw, and 7.25% rate. Change the rate or term to see how the repayment estimate moves.
Zero-rate boundary
A $300,000 home, $180,000 mortgage, 75% combined LTV limit, and $45,000 draw at 0%. This checks the no-interest formula branch.
HELOC vs. home equity loan
Both products use home equity, but the borrowing pattern and payment risk are different.
| Question | HELOC | Home equity loan |
|---|---|---|
| How you borrow | A revolving line where you can draw up to a limit | A lump sum funded at the start |
| Rate structure | Often variable, so the payment can change | Often fixed, though terms vary by lender |
| What this page estimates | Available credit plus draw and repayment payment snapshots | Not a home equity loan quote or amortization schedule |
| Best comparison | Flexibility and future payment risk | Known proceeds and a predictable payment assumption |
Important inputs and edge cases
These boundaries keep the result mathematically useful without pretending to reproduce a lender's underwriting system.
Home value is an estimate
The calculator cannot order an appraisal. A lender may use a different value, require a valuation, or cap the line below this simple result.
A zero rate is allowed
A 0% test rate shows zero draw interest and divides principal across the repayment term. It is a math boundary, not a typical offer.
No equity capacity
If the mortgage leaves no room under the selected LTV limit, available credit is zero. A drawn balance above that limit is rejected.
Fees are excluded
Annual fees, origination charges, closing costs, rate caps, minimum charges, and late fees are excluded. Add them when comparing offers.
Variable rates matter
Change the rate to test sensitivity. One rate cannot show how a benchmark change or lender margin may affect a future payment.
The balance can change
New draws, payments, and daily-interest rules change the balance. Recalculate with the updated amount instead of treating an old result as a quote.
Accuracy, privacy, and limitations
This HELOC calculator runs the math in your browser and does not request a lender connection or credit report. The result is not an approval, appraisal, rate lock, or personalized recommendation.
The model uses one balance, one annual rate, a monthly interest-only draw payment, and an even repayment schedule. Contracts may use daily rates, an index plus margin, floors or caps, minimums, capitalization, fees, or different dates.
Use the result to compare scenarios and prepare lender questions. Before signing, check the agreement for the line limit, margin, payment formula, rate adjustments, draw cutoff, term, and fees.
HELOC calculator FAQ
Quick answers to common questions about the inputs and the two payment estimates.
Ready to test another HELOC scenario?
Change the rate, draw amount, combined LTV, or repayment term to see which assumption moves the payment most.