HELOC Interest-Only Calculator - Home Equity Line Payment Calculator
Free HELOC interest-only calculator to calculate draw period payments, repayment phase costs, and payment shock. Calculate total interest for home equity lines of credit. Our calculator uses standard amortization formulas to project your interest-only payments during the draw period and principal plus interest payments during the repayment period, showing exactly how much your payment will increase.
Last updated: January 10, 2025
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Used to calculate loan-to-value ratio
Payment Analysis
$625.00/mo
Total interest: $75,000
$805.59/mo
Total repayment: $193,342
+28.9%
Payment increases by $180.59/month
Total Interest Paid
$168,342
Loan-to-Value
25.0%
$300,000
Yearly Payment Breakdown (First 10 Years)
HELOC Interest-Only Calculator Features
Typical period
10 Years
Interest-only payments on outstanding balance
Typical period
10-20 Years
Fully amortizing principal and interest payments
Typical increase
100-300%
Significant payment increase when principal repayment begins
Interest components
Draw + Repayment
Total interest paid over entire loan term
Typical max
80-85% CLTV
Combined loan-to-value including first mortgage
Shows details
Principal & Interest
Yearly breakdown of payments and remaining balance
Quick Example Result
$100,000 HELOC at 7.5% with 10-year draw and 20-year repayment:
Draw Payment
$625
Repayment
$806
Increase
+29%
Total Interest
$168K
How Our HELOC Interest-Only Calculator Works
Our HELOC interest-only calculator analyzes both phases of your home equity line of credit: the draw period (interest-only) and the repayment period (principal + interest). The calculator uses standard loan amortization formulas to project your payments in each phase, calculate the payment increase when the draw period ends, and show total interest costs over the life of the loan.
HELOC Payment Calculation Formulas
The dramatic payment increase from draw to repayment period (often 100-300%) is called "payment shock." In this example, the payment increases from $625 to $805 (29% increase) because we're amortizing over 20 years. A shorter repayment period would result in a much higher payment and greater payment shock.
Visualization of payment structure across draw and repayment periods
Understanding HELOC Structure
HELOCs have a unique two-phase structure. During the draw period (typically 10 years), you can borrow up to your credit limit, repay, and reborrow as needed, while only paying interest on the outstanding balance. This flexibility makes HELOCs popular for renovations, emergencies, and ongoing expenses. However, when the draw period ends, you can no longer borrow, and your payment increases significantly as you begin repaying the principal over the repayment period (typically 10-20 years).
- Draw period: Borrow/repay flexibility, interest-only payments, typically 10 years
- Repayment period: No new borrowing, principal + interest, typically 10-20 years
- Variable rate: Most HELOCs tied to prime rate, payments fluctuate with rate changes
- Payment shock: Transition to repayment can double or triple monthly payment
- Tax deduction: Interest may be deductible if used for home improvements
- Foreclosure risk: Your home secures the loan—default can result in foreclosure
Sources & References
- Consumer Financial Protection Bureau (CFPB) - What is a HELOC?Official consumer guidance on home equity lines of credit
- Truth in Lending Act (TILA) - Regulation ZFederal regulations governing HELOC disclosure requirements
- IRS Publication 936 - Home Mortgage Interest DeductionTax rules for HELOC interest deductibility
Exploring home financing options? Check out our mortgage recast calculator and borrowing power calculator.
Get Custom Calculator for Your PlatformHELOC Interest-Only Calculator Examples
HELOC Terms:
- HELOC Amount: $100,000
- Interest Rate: 7.5% (variable)
- Draw Period: 10 years
- Repayment Period: 20 years
- Home Value: $400,000
- LTV: 25%
Payment Calculation:
- Draw payment: $100,000 × (7.5% ÷ 12) = $625/mo
- Draw period total: $625 × 120 months = $75,000
- Repayment: $100K @ 7.5% over 20 yrs = $805/mo
- Repayment total: $805 × 240 months = $193,200
- Total interest: $75,000 + $93,200 = $168,200
- Payment increase: $805 - $625 = +$180 (29%)
Result: Payment increases from $625/month to $805/month (+29%)
Total interest paid over 30 years: $168,200. Consider paying principal during draw period to reduce future payments.
Shorter Repayment Example
$100K, 10-year repayment period
$1,207/mo (+93% increase)
Higher Rate Example
$100K @ 10% interest
$833/mo draw, $965/mo repayment
Frequently Asked Questions
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