Hipped Roof Calculator | Area, Height & Rafter Formula Guide

If you're building or estimating materials for a hipped roof, a Hipped Roof Calculator helps you determine:

• Roof height
• Rafter lengths
• Total roof surface area
• Roofing material requirements

A hipped roof has four sloping sides that meet at a ridge or peak. Unlike a gable roof, all sides slope downward toward the walls.

This guide explains the formulas used in a simple Hipped Roof Calculator using these inputs:

• Building Length (L)
• Building Width (W)
• Roof Pitch (Rise / Run)
• Eave Overhang (O) — Optional

Step 1: Adjusted Dimensions (Including Overhang)

If overhang is included:

$L^{\prime }=L+2O$

$W^{\prime }=W+2O$

If no overhang is provided, use original length and width.

Step 2: Roof Height (Ridge Height)

First calculate roof rise.

$H=\frac{\text{Rise}}{\text{Run}}\times \frac{W^{\prime }}{2}$

Step 3: Common Rafter Length

Using the Pythagorean Theorem:

$R=\sqrt{{\left(\frac{W^{\prime }}{2}\right)}^2+H^2}$

Step 4: Roof Surface Area

A simplified method to estimate total hipped roof area:

$A=2\times (R\times L^{\prime })$

(For precise hip geometry, triangular end sections can be calculated separately, but this formula works well for standard rectangular buildings.)

Step 5: Roofing Squares (Material Estimation)

Roofing is often sold in squares.

$\text{Squares}=\frac{A}{100}$

Full Example Calculation

Assume:

• Building Length (L) = 40 ft
• Building Width (W) = 24 ft
• Roof Pitch = 6/12
• Overhang (O) = 1 ft

Step 1: Adjusted Dimensions

$L^{\prime }=40+2\left(1\right)$

$L^{\prime }=42$

$W^{\prime }=24+2\left(1\right)$

$W^{\prime }=26$

Step 2: Roof Height

$H=\frac{6}{12}\times \frac{26}{2}$

$H=0.5\times 13=6.5$

Step 3: Rafter Length

$R=\sqrt{{13}^2+{6.5}^2}$

$R=\sqrt{169+42.25}$

$R=\sqrt{211.25}\approx 14.53$

Step 4: Roof Area

$A=2\times (14.53\times 42)$

$A=2\times 610.26$

$A\approx 1220.52$

Step 5: Roofing Squares

$\text{Squares}=\frac{1220.52}{100}$

$\text{Squares}\approx 12.21$

Final Results

For this example:

• Ridge Height = 6.5 ft
• Rafter Length ≈ 14.53 ft
• Total Roof Area ≈ 1,220 sq ft
• Roofing Material ≈ 12.2 squares

Why Use a Hipped Roof Calculator?

It helps you:

• Estimate roofing materials
• Plan framing
• Calculate ridge height
• Determine rafter length
• Budget your project accurately