Snow Load Calculator

Heavy snow accumulation on a roof can cause serious structural damage — the Snow Load Calculator estimates the total weight of snow pressing down on your roof so you know when it's time to act. Select your snow type (fresh, settled, wind-packed, or wet), then enter your snow thickness, roof length, roof width, and roof pitch to get the total snow weight in pounds. Secondary outputs include snow load (lbs/ft²), snow density, and roof area.

inches
feet
feet
degrees

Enter 0 for flat roofs

Results

Total Snow Weight

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Snow Load

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Snow Density

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Roof Area

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Frequently Asked Questions

What's the weight of snow on a roof?

The weight of snow on a roof depends on the snow type and thickness. Fresh snow weighs about 5-12 lbs/ft³, while wet snow can weigh 15-20 lbs/ft³. A foot of wet snow can add 15-20 pounds per square foot to your roof.

Should I shovel my roof today?

You should remove snow if the total load exceeds your roof's design capacity, typically 20-30 lbs/ft² for residential roofs. Look for warning signs like sagging, creaking sounds, or cracks in walls or ceilings.

How does snow type affect roof load calculations?

Different snow types have varying densities. Fresh powder snow is lightest at 5-12 lbs/ft³, while very wet snow can reach 15-20 lbs/ft³. Wind-packed and settled snow fall between these ranges.

What are the warning signs of excessive snow load?

Watch for sagging roof lines, cracking sounds from the structure, doors or windows that stick, cracks in drywall or masonry, and severe ice dams. These indicate your roof may be overstressed.

How do I safely remove snow from my roof?

Use a roof rake from the ground when possible, remove snow in small sections, avoid getting on the roof yourself, and consider hiring professionals for steep or high roofs. Never use metal tools that could damage roofing materials.

Does roof pitch affect snow load calculations?

Yes, steeper roofs shed snow more easily, reducing the actual load. Roofs with slopes greater than 30° typically don't retain significant snow loads, while flat roofs bear the full weight of accumulated snow.