Snow Weight Calculator
Use this professional snow weight calculator to estimate the total mass and roof load of accumulated snow. Whether you are a homeowner concerned about roof safety or a contractor planning snow removal, understanding the density and weight of snow is critical for structural integrity and logistical planning.
The length of the roof, driveway, or deck area.
Please enter a valid positive length.
The width of the area covered in snow.
Please enter a valid positive width.
Average depth of the snow accumulation.
Please enter a valid positive depth.
Fresh, Fluffy Snow (3 lb/ft³)
Average Fresh Snow (7 lb/ft³)
Settled / Packed Snow (15 lb/ft³)
Wet / Heavy Snow (25 lb/ft³)
Wind-Packed Drifts (35 lb/ft³)
Solid Ice (57 lb/ft³)
Select the type of snow to estimate density.
Total Estimated Weight
9,000 lbs
(Approx. 4.50 Tons)
Roof Load (Pressure)
15.0 PSF
Total Volume
600 ft³
Water Equivalent
144 Gal
Formula Used: Weight = Area (ft²) × Depth (ft) × Snow Density (lb/ft³).
Load (PSF) = (Depth in inches / 12) × Density.
Load (PSF) = (Depth in inches / 12) × Density.
Calculated Load vs. Typical Structural Limits
■ Your Load
■ Standard Roof Limit (20psf)
■ High Load Limit (40psf)
What is a Snow Weight Calculator?
A snow weight calculator is an essential tool for homeowners, facility managers, and structural engineers to estimate the mass of snow accumulation on a specific surface area. By inputting the dimensions of the area and the depth of the snow, combined with the specific snow density, the calculator determines the total weight in pounds or tons.
This tool is particularly useful for assessing roof snow load—the downward force exerted by snow on a roof structure. Knowing the snow weight helps prevent structural failures, collapses, and long-term damage caused by excessive weight. While fresh powder is relatively light, wet snow or ice can weigh significantly more, posing hidden dangers to residential and commercial structures.
Snow Weight Formula and Mathematical Explanation
To calculate the weight of snow, we use a physics-based formula that accounts for volume and density. The snow weight calculator performs these conversions automatically, but understanding the math is vital for accurate safety assessments.
The core formula is:
Weight (lbs) = Area (ft²) × Depth (ft) × Density (lb/ft³)
Where:
1. Area is Length × Width.
2. Depth must be converted from inches to feet (Inches ÷ 12).
3. Density varies based on the water content of the snow.
| Snow Type | Density (lb/ft³) | Description | Relative Weight |
|---|---|---|---|
| Fresh / Powder | 3 – 7 | Light, fluffy, newly fallen snow. | Very Light |
| Settled Snow | 12 – 18 | Snow that has sat for days or been wind-packed. | Moderate |
| Wet Snow | 20 – 30 | Heavy, watery snow often in spring. | Heavy |
| Ice | 57 | Solid frozen water. | Extreme |
Practical Examples (Real-World Use Cases)
Example 1: Residential Roof Safety
Scenario: A homeowner has a flat roof measuring 30ft by 20ft. After a winter storm, there is 24 inches of settled snow on the roof. They need to know if this exceeds a standard 20 PSF (pounds per square foot) live load limit.
- Area: 30′ × 20′ = 600 ft²
- Depth: 24 inches = 2 feet
- Density: Settled snow is approx. 15 lb/ft³
- Calculation: 600 ft² × 2 ft × 15 lb/ft³ = 18,000 lbs
- Roof Load (PSF): 18,000 lbs / 600 ft² = 30 PSF
Result: The load is 30 PSF, which exceeds the standard 20 PSF limit. The homeowner should consider professional snow removal immediately to prevent structural damage.
Example 2: Driveway Snow Removal
Scenario: A contractor is quoting a job to clear a 50ft by 10ft driveway covered in 6 inches of wet, heavy snow. They need to estimate the weight to choose the right equipment.
- Area: 50′ × 10′ = 500 ft²
- Depth: 6 inches = 0.5 feet
- Density: Wet snow is approx. 25 lb/ft³
- Calculation: 500 ft² × 0.5 ft × 25 lb/ft³ = 6,250 lbs
Result: The total weight is over 3 tons (6,250 lbs). A simple snow blower might struggle; a plow or skid steer would be more efficient for this snow weight calculator estimation.
How to Use This Snow Weight Calculator
- Measure Area: Enter the Length and Width of the space (roof, deck, ground) in feet.
- Measure Depth: Enter the average depth of the snow in inches. If the snow is uneven (drifted), use the average or the deepest point for a safety margin.
- Select Snow Type: Choose the description that best matches your snow conditions. "Wet" snow is sticky and heavy; "Fresh" snow is light and powdery.
- Analyze Results:
- Total Weight: The total mass on the structure.
- Roof Load (PSF): The most critical metric for structural safety. Compare this against your building's design specifications.
Key Factors That Affect Snow Weight Results
Using a snow weight calculator provides an estimate, but several real-world factors influence the actual load:
- Water Content (Moisture): The ratio of water to air determines density. Wet snow can weigh 4-5 times as much as fresh powder for the same depth.
- Compaction & Time: Over time, snow settles under its own weight. A 10-inch layer might settle to 6 inches, but the total weight remains the same, meaning density increases.
- Ice Damming: Cycles of melting and refreezing create ice layers at the bottom of the snowpack. Ice is significantly heavier (57 lb/ft³) than snow and can drastically skew snow weight calculator results if not accounted for.
- Rain on Snow: Rain adds massive weight to existing snow without necessarily increasing depth. The snow acts like a sponge, absorbing the rainwater.
- Roof Pitch: On pitched roofs, snow may slide off or accumulate unevenly in valleys. While the calculator gives a total weight based on flat area, the distribution of that weight varies on sloped surfaces.
- Drifting: Wind causes snow to accumulate deeper in specific areas (drifts). A roof might have an average depth of 12 inches but a 4-foot drift in one corner, creating a localized point of structural stress.
Frequently Asked Questions (FAQ)
How much weight can a standard roof hold?
Most residential roofs in snow-prone areas are designed for a live load of at least 20 PSF (pounds per square foot). However, newer codes in heavy snow regions may require 40 PSF or higher. Consult your local building codes or a structural engineer.
What is 1 inch of snow in water equivalent?
The general rule of thumb is a 10:1 ratio for fresh snow, meaning 10 inches of snow equals 1 inch of water. However, for wet snow, the ratio can be closer to 5:1 or even 3:1, making the snow much heavier.
Does this calculator account for ice?
Yes, if you select "Ice" from the Snow Type dropdown. If you have a layer of snow and a layer of ice, calculate them separately and add the Total Weights together.
Why is "PSF" important for snow load?
PSF (Pounds per Square Foot) is the standard unit engineers use to define load capacity. Knowing the Total Weight is less useful than knowing if the weight per square foot exceeds the structure's rating.
Is wet snow heavier than dry snow?
Yes, significantly. Wet snow contains more liquid water and less air. While dry snow is mostly air bubbles, wet snow is dense, often weighing 20+ lbs per cubic foot compared to 3-5 lbs for dry snow.
Should I shovel my roof?
If your calculated load approaches your roof's design limit (often 20-25 PSF), removal is recommended. However, roof clearing is dangerous; using a roof rake from the ground or hiring professionals is safer than climbing on a slick roof.
How accurate is a snow weight calculator?
It is an estimation tool. The exact density of snow varies inch by inch. This calculator provides a reasonable safety baseline, but always err on the side of caution with structural loads.
Does rain increase the snow load?
Absolutely. Rain falling on snow does not run off; it is absorbed. This can double the weight of the snow pack rapidly without visually changing the depth.
Related Tools and Resources
- Roof Load Capacity Calculator – Determine if your roof structure is safe under current loads.
- Snow Density Guide – Detailed breakdown of different snow types and their water content.
- Water Weight Calculator – Calculate the weight of water for drainage and storage.
- Winter Roof Maintenance Guide – Tips for preventing ice dams and structural damage.
- Ice Dam Weight Estimator – Specifically for calculating heavy ice buildup on eaves.
- Rainfall to Snow Converter – Estimate snow depth based on precipitation forecasts.