Free snow load calculator for roofs. Calculate snow loads using simple depth-based method or ASCE 7 standards with exposure, thermal, and importance factors.
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Our snow load calculator helps engineers, contractors, and homeowners determine the weight of snow on roofs. Choose the simple depth-based method for quick estimates or use the ASCE 7 engineering standard for precise structural calculations.
Snow load is the weight of accumulated snow on a roof, measured in pounds per square foot (psf) or kilonewtons per square meter (kN/m²). It varies based on snow density (fresh vs. packed), depth, and roof characteristics. Structural engineers use ASCE 7 to calculate design snow loads.
ASCE 7 Flat Roof Formula
Pf = 0.7 × Ce × Ct × Is × PgPrevent roof collapse by ensuring structures can handle expected snow loads.
Meet local building code requirements for snow load resistance.
Know when accumulated snow exceeds safe limits and needs removal.
Engineers calculate design snow loads for new construction.
Homeowners assess whether to remove snow after heavy storms.
Facility managers monitor snow loads on flat commercial roofs.
Document snow loads for potential insurance claims.
Snow weight varies dramatically by type. Fresh fluffy snow weighs about 5-10 lb/ft³, while packed snow is 15-25 lb/ft³, and wet heavy snow can reach 25-35 lb/ft³. Ice is even heavier at 57 lb/ft³.
Ground snow load is the weight of snow on the ground, specified by ASCE 7 for each geographic location. It's the starting point for calculating roof snow loads. Values range from 0 in warm climates to over 300 psf in mountain regions.
Most residential roofs are designed for 20-40 psf of snow load. This equals roughly 3-4 feet of fresh snow or 1-2 feet of packed snow. Always check local building codes for specific requirements.
Yes! Steeper roofs shed snow more easily. ASCE 7 applies a slope reduction factor (Cs) that decreases the design load for roofs steeper than 30° (warm roofs) or 45° (cold roofs).