MCPCalc

HELOC Calculator

Calculate home equity line of credit availability and payments.

Scratchpad (not saved)

$

Current market value of your home

$

Remaining balance on your mortgage

%

Maximum combined loan-to-value ratio (typically 80%)

%

Annual interest rate on the HELOC

$

Amount you plan to draw (0 = show max available)

Time to repay the drawn amount

What This Calculator Does

Estimate line-of-credit payment behavior under draw and repayment phases so you can plan around variable borrowing costs.

It combines Home Value, Mortgage Balance, Max LTV Ratio, HELOC Interest Rate to estimate Available Credit Line, Current Home Equity, Current LTV.

Formula & Method

Core equations: Available credit is based on LTV: \text{Credit} = \text{Home Value} \times \text{Max LTV} - \text{Mortgage Balance} Interest-only payment: P_{IO} = \frac{\text{Draw} \times r}{12} Fully amortized repayment uses: P = D \cdot \frac{r(1+r)^n}{(1+r)^n - 1} where D is the draw amount, r is the monthly rate, and n is the repayment term in months. Inputs are applied in base units, then derived metrics are computed from the same equations and rounded for display.

Notation used in the formulas: R = Available Credit Line; x_{1} = Home Value; x_{2} = Mortgage Balance; x_{3} = Max LTV Ratio; x_{4} = HELOC Interest Rate; x_{5} = Amount to Draw; x_{6} = Repayment Period.

Method summary: inputs are normalized to consistent units, core equations are evaluated, then secondary values are derived and rounded for display.

Use this before opening or using a HELOC to stress test affordability under higher-rate assumptions.

Inputs Used

  • Home Value: Current market value of your home
  • Mortgage Balance: Remaining balance on your mortgage
  • Max LTV Ratio: Maximum combined loan-to-value ratio (typically 80%)
  • HELOC Interest Rate: Annual interest rate on the HELOC
  • Amount to Draw: Amount you plan to draw (0 = show max available)
  • Repayment Period: Time to repay the drawn amount

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