Simple Mortgage Calculator

Home Equity Line of Credit (HELOC) Calculator

Estimate your borrowing power, interest-only draw payments, and repayment P&I.

Use our HELOC calculator to estimate how much you may be able to borrow against your home and what your payments could look like during the interest-only draw period and the later repayment period. Enter your home’s value, your current mortgage balance, your lender’s LTV limit, and the rate inputs (index + margin) to see a clear breakdown—plus a repayment amortization on a chosen draw amount.

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Payments Overview

Repayment Balance Over Time

Repayment Amortization (first 24 months)

MonthPrincipalInterestEnding Balance
1$129.18$385.42$49,870.82
2$130.18$384.42$49,740.65
3$131.18$383.42$49,609.47
4$132.19$382.41$49,477.28
5$133.21$381.39$49,344.07
6$134.24$380.36$49,209.83
7$135.27$379.33$49,074.56
8$136.31$378.28$48,938.25
9$137.36$377.23$48,800.89
10$138.42$376.17$48,662.46
11$139.49$375.11$48,522.97
12$140.56$374.03$48,382.41
13$141.65$372.95$48,240.76
14$142.74$371.86$48,098.02
15$143.84$370.76$47,954.18
16$144.95$369.65$47,809.23
17$146.07$368.53$47,663.16
18$147.19$367.40$47,515.97
19$148.33$366.27$47,367.64
20$149.47$365.13$47,218.17
21$150.62$363.97$47,067.55
22$151.78$362.81$46,915.77
23$152.95$361.64$46,762.81
24$154.13$360.46$46,608.68

Enter HELOC Details

Results Summary

Available equity
$200,000.00
LTV now
60.0%
Estimated line (max)
$100,000.00
CLTV with chosen draw
70.0%
Estimated APR (Index + Margin)
9.250%
Interest-only (chosen draw)
$385.42
Interest-only (fully utilized)
$770.83
Repayment P&I (monthly)
$514.60
Total interest (repayment phase)
$42,627.31

Interest-only payments apply during the draw period and vary with the drawn balance and rate. Repayment P&I is calculated by amortizing the chosen draw over the repayment term using the current APR. Actual lender terms, caps, and adjustments may change these figures.

How to Use the HELOC Calculator

Start with your home value and current mortgage balance. Set an LTV limit (many lenders use 80–85%). Enter an index (e.g., latest U.S. Prime) and your estimated margin, then choose a draw period and repayment term. Optionally add a ZIP code and credit score range for context. Finally, pick a draw amount (e.g., full line or a smaller amount) to preview interest-only payments and the later repayment schedule.

What Is a HELOC?

A HELOC is a revolving line of credit secured by your home’s equity. During the draw period, you can borrow, repay, and re-borrow up to your credit limit, usually making interest-only payments. In the repayment period, the outstanding balance is amortized into principal and interest payments.

Understanding the Draw and Repayment Periods

  • Draw period: Typically 5–10 years; minimum payment often covers interest only.
  • Repayment period: Principal and interest payments over a fixed term (e.g., 10–20 years).

HELOC vs. Home Equity Loan

A home equity loan is a fixed lump sum with a fixed rate. A HELOC is revolving, usually with a variable rate (Index + Margin). Some lenders also offer fixed-rate draw options on a HELOC.

How Lenders Determine Your HELOC Amount (LTV)

Many lenders cap combined loan-to-value (CLTV) at 80–85%. Your estimated line is: (Home Value × LTV Limit) − Existing Mortgage Balance. Qualification also considers credit, income, debt, and property factors.

Who a HELOC Is Right For & Common Uses

  • Home improvements or renovations
  • Debt consolidation (compare rates and fees)
  • Major purchases or education expenses
  • Emergency or opportunity fund flexibility

Frequently Asked Questions

Does my rate change over time?

Most HELOCs are variable: Rate = Index + Margin, and the index can move. Check your lender’s caps and adjustment schedule.

Can I lock a fixed rate on part of my HELOC?

Many lenders allow fixed-rate draws. This page models the variable-rate case; fixed draws typically amortize like a standard loan.