Quick start
- Open the HELOC Calculator.
- Enter home value, current mortgage balance, credit line, current draw, rate, repayment years, and max CLTV.
- Use the first example, "$30k draw: $450,000 home, $260,000 mortgage, $80,000 line, $30,000 drawn, 9%, 15-year repayment, 85% CLTV cap", if you want to see a filled-out estimate before entering your own values.
- Calculate, read the formula line, then copy the result only after the amounts, percentages, time periods, or assumptions look right.
Best uses
Start here if one of these sounds like your job. The examples below show which inputs matter most.
- Estimate monthly interest-only payment on a current draw.
- Estimate repayment payment after the draw period.
- Check available equity against a line limit.
- Compare HELOC with a fixed home equity loan.
What this calculator is for
The HELOC Calculator separates the draw-period interest-only estimate from the later repayment estimate. That matters because the cheap-looking draw payment can jump when principal has to be repaid.
Good fit examples: Estimate monthly interest-only payment on a current draw. Estimate repayment payment after the draw period.
What to enter
Finance estimates are sensitive to small input changes. Check whether a field expects a monthly amount, annual amount, dollar value, or percent before calculating.
- Enter home value, current mortgage balance, credit line, current draw, rate, repayment years, and max CLTV.
- Use current draw for the amount already borrowed, not the full credit line. A $80,000 line with $30,000 drawn should not be treated like $80,000 of debt.
- Use the rate as a planning rate because many HELOCs are variable. Check the index, margin, teaser period, and rate cap in the lender papers.
Example walkthrough
Try the calculator example: $30k draw: $450,000 home, $260,000 mortgage, $80,000 line, $30,000 drawn, 9%, 15-year repayment, 85% CLTV cap. The example result is $225.00 interest-only estimate, about $304.28 repayment estimate, $122,500 available equity, and 64.44% CLTV on the draw.
- Try this example: $450,000 home value, $260,000 mortgage balance, $80,000 credit line, $30,000 current draw, 9% rate, 15-year repayment, and 85% max CLTV.
- The draw-period interest-only estimate is $225.00/month. If that same $30,000 draw is repaid over 15 years at 9%, the repayment estimate is about $304.28/month.
- The available-equity estimate is $122,500 at an 85% CLTV cap, and the CLTV on the current draw is 64.44%.
Formula and steps
In plain language: The calculator estimates available equity as home value times max CLTV minus current mortgage balance. It computes draw-period interest-only payment from current draw times monthly rate, then estimates repayment payment by amortizing the current draw over the entered repayment years. Available equity = home value x max CLTV - current mortgage balance. Interest-only payment = current draw x annual rate / 12. Repayment payment amortizes the current draw over the repayment years.
If the estimate looks surprising, check the formula and inputs before using the answer in a budget, comparison, or planning note.
How to read the answer
Start with the headline result. Then read the supporting lines to see what made the number larger or smaller, such as rates, time periods, costs, taxes, fees, discounts, or contributions.
- Interest-only payment is based only on the current draw and rate.
- Repayment payment estimate shows what the drawn balance might cost if paid down over the repayment period.
- Combined LTV on draw uses current mortgage balance plus current draw, not the full credit line.
- Available equity is a rough borrowing-room screen. A lender can still use a different appraisal, credit rule, income review, or CLTV cap.
Common mistakes to avoid
Most bad finance estimates come from mixing rates, terms, monthly amounts, and annual amounts. The other common mistake is using a planning estimate as if it were a final quote.
- Do not treat the interest-only payment as the forever payment.
- Do not ignore variable rates, teaser rates, index and margin terms, line freezes, minimum draws, annual fees, transaction fees, balloon payments, and lender line rules.
- Do not forget that missing payments can put the home at risk.
- Do not assume HELOC interest is tax deductible unless the money use and IRS rules match.
What to try next
A related money tool can help check the same question from another angle before you rely on one result.
- Use Home Equity Loan Calculator for a fixed lump-sum option.
- Use APR Calculator if fees make a quote hard to compare.
- Before signing, compare the lender disclosure, draw period, repayment period, variable-rate terms, right to cancel, fees, and what happens if the line is frozen.
Sources and estimate notes
This guide links to public financial, consumer, statistical, or tax references where they are useful for understanding the calculator context.
Source links improve transparency, but they do not turn a quick calculator into professional advice or a final loan, tax, payroll, or investment answer.
Worked examples for HELOC Calculator
$225.00 interest-only estimate, about $304.28 repayment estimate, $122,500 available equity, and 64.44% CLTV on the draw
$437.50 interest-only estimate, about $530.23 repayment estimate, $160,000 available equity, and 68.33% CLTV on the draw
$79.17 interest-only estimate, about $129.40 repayment estimate, $94,000 available equity, and 57.89% CLTV on the draw
FAQ in plain language
When should I use the HELOC Calculator?
Use it when you want to test the exact inputs on this page: Estimate monthly interest-only payment on a current draw. Estimate repayment payment after the draw period. The result is a check against your assumptions, not proof that a lender, tax app, broker, platform, or provider will use the same number.
What do the main HELOC Calculator inputs mean?
Home value means the property value you want to test before any lender appraisal changes it. Current mortgage balance means what you still owe on the first mortgage or other senior liens. Credit line means the maximum line size you want to compare with the available-equity estimate. Current draw means the amount already borrowed from the line, not the full line limit. Interest rate means the rate used for the monthly estimate. Many HELOC rates can move over time. Repayment period means the years used to estimate the later principal-and-interest payment. Max combined LTV means the cap used to estimate possible borrowing room after the current mortgage.
What is the main HELOC payment this calculator shows?
The headline answer is the interest-only estimate for the current draw. If you have drawn $30,000 at 9%, the estimate is $225.00 per month before fees. That is not the same as the later repayment payment.
Why is the repayment payment higher than the interest-only payment?
During repayment, the calculator pays down the drawn balance over the repayment years. A $30,000 draw at 9% over 15 years is about $304.28 per month, which is higher than the $225.00 interest-only estimate because principal is being repaid too.
Does the calculator use the full credit line or the current draw?
It uses the current draw for the payment estimates. The credit line is shown separately because a $80,000 line with only $30,000 drawn should not be treated like $80,000 of borrowed money.
What does CLTV mean on a HELOC?
CLTV means combined loan-to-value. This page compares your current mortgage plus the current HELOC draw with the home value. It also estimates available equity from the max CLTV cap you enter.
Can my HELOC payment change later?
Yes. CFPB and FTC guidance both warn that HELOCs often have variable rates and different draw and repayment periods. A rate change, draw change, fee, freeze, balloon payment, or repayment-period switch can move the real payment.
Related tools
- Home Equity Loan Calculator Estimate a fixed home equity loan payment, borrowing room, and combined loan-to-value.
- Loan Calculator Estimate a fixed monthly loan payment, total paid, and total interest from amount, rate, and term.
- Mortgage Calculator Estimate monthly principal, interest, taxes, insurance, PMI, and HOA costs.
Keep exploring
If this guide is close but not exact, these links keep you near the same kind of problem.
- Finance Browse the full category for related tools that help with the same job.
- All free tools Search the complete Access Free Tools library by task, category, or tool name.
- All calculator and utility guides Find more plain-language examples, formulas, mistakes, and result explanations.
- Free calculator resources Start here when you are not sure which calculator page fits.
Privacy and copying results
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Use Copy answer when you want to save the inputs and result in notes, homework, a message, or a project list. Check the units, labels, and limits before copying.