Roofing Calculator

sq ft
°
%
x:12
sq ft
USD/sq ft
USD

How to Calculate Roofing Dimensions and Cost

  1. House Dimensions:
    Measure the length and width of your house to calculate the base area.
    • Formula: \text{Base Area} = \text{House Length} \times \text{House Width}
  2. Roof Pitch:
    Use any one value (degree, percentage, or x:12 ratio) to calculate the others.
    • Formulas: \text{Pitch Percentage} = \tan(\text{Pitch Degree}) \times 100 \text{Pitch Ratio (x:12)} = \tan(\text{Pitch Degree}) \times 12
  3. Roof Area:
    Multiply the base area by a pitch factor derived from the roof pitch.
    • Formula: \text{Roof Area} = \text{Base Area} \times \sqrt{1 + (\tan(\text{Pitch Degree}))^2}
  4. Roof Cost:
    Multiply the roof area by the unit price of roofing material.
    • Formula: \text{Total Cost} = \text{Roof Area} \times \text{Unit Price}

Example Calculation

Let’s say:

  • House Length = 40 ft
  • House Width = 30 ft
  • Roof Pitch = 30°
  • Unit Price = $3/sq ft
  1. Base Area: 40 \times 30 = 1200 \, \text{sq ft}
  2. Pitch Factor: \sqrt{1 + (\tan(30°))^2} = 1.15
  3. Roof Area: 1200 \times 1.15 = 1380 \, \text{sq ft}
  4. Total Cost: 1380 \times 3 = 4140 \, \text{USD}