Free Construction Calculator
All-in-one roofing and construction calculator. Calculate pitch, roof area, rafter length, hip/valley, volume, and material quantities. No signup required — works on mobile and desktop.
Pitch Degree ↔ Ratio Converter
Convert between pitch degrees and ratios (e.g. 25° = 1:2.144)
Ratio
1:2.145
Rafter Pitch Factor
1.1034
Roof cross-section at 25.0° pitch
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Free Quote GeneratorHow to use this calculator
Select a calculator tab above, enter your measurements, and get instant results. Toggle between metric (m, m², m³) and imperial (ft, ft², ft³) units using the toggle at the top. All calculations run in your browser — no data is sent anywhere.
Common roofing calculations
Pitch factor: The pitch factor converts a flat (plan) measurement to the actual sloped roof area. For a rafter-type roof at 25°, the factor is approximately 1.103, meaning a 100 m² plan area has ~110.3 m² of actual roofing surface.
Rafter length: Calculated as half the span divided by the cosine of the pitch angle. For a 10m span at 30°, each rafter is (10/2) / cos(30°) ≈ 5.77m.
Hip/Valley length: Uses a compound angle formula combining the roof pitch with the 45° hip/valley angle. The hip factor is √(rafter_factor² + 1).
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Frequently asked questions
Is this calculator free?
Yes, completely free with no signup required. It works entirely in your browser.
Does it work on mobile?
Yes, the calculator is fully responsive and optimized for mobile use on-site.
Can I use imperial units?
Yes, toggle between metric and imperial at any time. All calculators support both.