❄️ Roof Snow Load Calculator
Estimate snow weight and roof load capacity
Enter your roof area, snow depth, snow type, and roof pitch. We'll calculate the total snow weight and how close you are to your roof's capacity.
Smart Roofing Calculator — Roof Snow Load Calculator — smartroofingcalculator.com/snow-load-calculator/ — printed
Total roof surface area
Average depth on roof
Higher pitch = less accumulation
20–40 PSF typical residential
❄️ Fresh snow weighs ~1.25 lbs/sq ft per inch of depth.
🛠️ How This Calculator Works
This calculator multiplies snow depth by weight-per-inch (varies by snow type), then applies a pitch reduction factor. It compares the result against your roof's structural capacity to show load percentage.
📐 Formula
Load PSF = Snow Depth × Weight/Inch × Pitch Factor | Total Weight = Load PSF × Roof Area📝 Example Calculation
For a 2,000 sq ft roof with 18" of packed snow, 6/12 pitch: • Packed snow: 3.0 lbs/sq ft per inch • Raw load: 18 × 3.0 = 54 PSF • Pitch factor (6/12): 0.7 • Adjusted load: 54 × 0.7 = 37.8 PSF • Total weight: 75,600 lbs (37.8 tons) • At 30 PSF capacity: 126% — REMOVE SNOW IMMEDIATELY
💡 Pro Tips from Roofers
- Use a roof rake from the ground — never climb on a snow-loaded roof.
- Remove snow in strips from eave to ridge to prevent uneven loading.
- Watch for ice dams at eaves — they add concentrated weight.
- Drifting snow on leeward sides can be 2–3× deeper than windward sides.
- If load exceeds 75% of capacity, start removal immediately.
❓ Frequently Asked Questions
How much snow can my roof hold?
Most residential roofs support 20–40 PSF (pounds per square foot) of snow load. This equals roughly 4–8 feet of fresh snow, 2–4 feet of packed snow, or 4–8 inches of ice. Check your local building code for your specific ground snow load requirement.
When should I remove snow from my roof?
Remove snow when accumulation exceeds 2 feet of fresh snow or you notice sagging, cracking sounds, or doors/windows sticking. Never wait for the roof to reach its maximum capacity.
Does roof pitch affect snow load?
Yes. Steeper roofs shed snow more easily. The snow load reduction factor decreases with steeper pitches. A 6/12 pitch has about 70% of the ground snow load, while a 12/12 pitch has about 40%.
What is ground snow load?
Ground snow load (Pg) is the weight of snow on flat ground in your area, measured in PSF. It's determined by your geographic location and elevation. Values range from 0 PSF in southern states to 100+ PSF in mountain regions.
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About the Smart Calculator Team
We build free, accurate construction calculators for homeowners and contractors. This article is part of our roofing knowledge base — we also publish guides and tools for other home improvement projects:
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Checking what the framing can carry? The roof load capacity calculator combines dead, live and snow loads.
· Reviewed by the Smart Roofing Calculator editorial team