HELOC Calculator
Enter your home value, mortgage and HELOC rate to see how much you can borrow and what you pay in the draw and repayment periods.
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What you still owe on your first mortgage.
Combined loan-to-value limit, usually 80% to 90%.
Variable: usually the prime rate plus a margin.
- Maximum credit line
- $90,000
- Home equity
- $150,000
- CLTV after borrowing
- 75%
- Interest in the draw period
- $37,500.00
- Interest in the repayment period
- $46,671.18
- Total interest
- $84,171.18
| Rate | Draw-period payment | Repayment payment |
|---|---|---|
| 7.5% (today) | $312.50 | $402.80 |
| 8.5% (+1 pt) | $354.17 | $433.91 |
| 9.5% (+2 pt) | $395.83 | $466.07 |
| 10.5% (+3 pt) | $437.50 | $499.19 |
How this was calculated
- Credit line: $400,000.00 × 85% − $250,000.00 = $90,000.00
- Draw period: $50,000.00 × 7.5% ÷ 12 = $312.50 a month
- Repayment: $50,000.00 amortized over 240 months at 7.5% = $402.80 a month
| Year | Phase | Paid | Interest | Principal | Balance |
|---|---|---|---|---|---|
| 1 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 2 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 3 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 4 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 5 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 6 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 7 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 8 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 9 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 10 | Draw | $3,750 | $3,750 | $0 | $50,000 |
| 11 | Repay | $4,834 | $3,712 | $1,122 | $48,878 |
| 12 | Repay | $4,834 | $3,625 | $1,209 | $47,670 |
| 13 | Repay | $4,834 | $3,531 | $1,302 | $46,367 |
| 14 | Repay | $4,834 | $3,430 | $1,404 | $44,964 |
| 15 | Repay | $4,834 | $3,321 | $1,513 | $43,451 |
| 16 | Repay | $4,834 | $3,204 | $1,630 | $41,821 |
| 17 | Repay | $4,834 | $3,077 | $1,757 | $40,064 |
| 18 | Repay | $4,834 | $2,941 | $1,893 | $38,172 |
| 19 | Repay | $4,834 | $2,794 | $2,040 | $36,132 |
| 20 | Repay | $4,834 | $2,635 | $2,198 | $33,933 |
| 21 | Repay | $4,834 | $2,465 | $2,369 | $31,565 |
| 22 | Repay | $4,834 | $2,281 | $2,553 | $29,012 |
| 23 | Repay | $4,834 | $2,083 | $2,751 | $26,261 |
| 24 | Repay | $4,834 | $1,869 | $2,965 | $23,296 |
| 25 | Repay | $4,834 | $1,639 | $3,195 | $20,102 |
| 26 | Repay | $4,834 | $1,391 | $3,443 | $16,659 |
| 27 | Repay | $4,834 | $1,124 | $3,710 | $12,949 |
| 28 | Repay | $4,834 | $836 | $3,998 | $8,951 |
| 29 | Repay | $4,834 | $525 | $4,308 | $4,643 |
| 30 | Repay | $4,834 | $191 | $4,643 | $0 |
Estimates only: lenders accrue interest daily and rates change with the prime rate. Educational, not financial advice.
How a HELOC payment is calculated
A home equity line of credit has two phases, and this HELOC calculator shows both. During the draw period (usually 10 years) most lenders only require interest: balance × APR ÷ 12. In the repayment period (usually 20 years) you can no longer borrow and the balance is paid off like a mortgage: payment = B·r ÷ (1 − (1 + r)−n), with r the monthly rate and n the number of months. How much you can borrow depends on your equity: lenders cap the combined loan-to-value (CLTV), so the line is home value × max CLTV minus what you owe.
Worked example
A $400,000 home with a $250,000 mortgage and an 85% CLTV limit supports a line of up to $90,000 ($340,000 − $250,000). Borrow $50,000 at 7.5% and the draw-period payment is $312.50 a month. When repayment starts the payment rises to $402.80, a $90.30 jump, for 20 years. Total interest comes to $84,171.18: $37,500.00 in the interest-only years and $46,671.18 while repaying. Paying the same $50,000 off over 30 years from the start ($349.61 a month) would cost $75,858.61 in interest, $8,312.57 less, because principal starts falling right away.
What a HELOC costs per $10,000
| APR | Interest-only | Repay over 10 yr | Over 15 yr | Over 20 yr |
|---|---|---|---|---|
| 6% | $50.00 | $111.02 | $84.39 | $71.64 |
| 7% | $58.33 | $116.11 | $89.88 | $77.53 |
| 8% | $66.67 | $121.33 | $95.57 | $83.64 |
| 9% | $75.00 | $126.68 | $101.43 | $89.97 |
| 10% | $83.33 | $132.15 | $107.46 | $96.50 |
Scale linearly: $35,000 at 8% interest-only is 3.5 × $66.67 = $233.33 a month.
The rate is variable
HELOC rates are typically the prime rate plus a margin, so the payment moves when the Federal Reserve moves rates. The calculator's stress table shows the same balance at +1, +2 and +3 points: in the example, a 2-point rise lifts the repayment payment from $402.80 to $466.07. Budget for the higher figure, and check whether your lender offers a fixed-rate option on part of the balance.
Is HELOC interest tax deductible?
Sometimes. IRS Publication 936 (2025) says home equity interest is deductible only if the money is used to buy, build or substantially improve the home that secures the line, and only if you itemize. Total mortgage plus HELOC debt counts toward a $750,000 limit ($375,000 married filing separately). A HELOC used for a car, tuition or credit card debt gives no deduction. Compare the after-tax cost with a fixed loan using the interest calculator, or see what paying down card debt saves with the credit card payoff calculator.
Frequently asked questions
How is a HELOC payment calculated?
In the draw period most HELOCs are interest-only: balance × APR ÷ 12, so $50,000 at 7.5% costs $312.50 a month. In the repayment period the balance is amortized, which is $402.80 a month over 20 years at the same rate.
How much can I borrow with a HELOC?
Home value × the lender's maximum combined loan-to-value, minus your mortgage balance. A $400,000 home with a $250,000 mortgage and an 85% CLTV limit supports a line of up to $90,000.
What happens when the HELOC draw period ends?
You can no longer borrow and start repaying principal plus interest, usually over 20 years. The payment jumps even if the rate stays the same: $50,000 at 7.5% goes from $312.50 interest-only to $402.80 over 20 years, 29% more.
Is HELOC interest tax deductible?
Only if the money is used to buy, build or substantially improve the home that secures it, you itemize, and your total home debt is within $750,000 ($375,000 married filing separately), per IRS Publication 936.
What is the payment on a $100,000 HELOC?
At 8% it is $666.67 a month interest-only, and $836.44 a month once it is repaid over 20 years. Every $10,000 adds $66.67 and $83.64 respectively.