Roof Snow Load Calculator
Estimate how much the snow, ice or water on a roof weighs, in total and per square foot, from its depth.
Change the values and press Calculate to work out your own figures.
Enter the roof's footprint and the depth of snow.
Show the working
- load per sq ft = depth (ft) × density
- weight = load × footprint
How to use it
Enter the roof's footprint and the depth of snow.
Lengths can be decimals, fractions or tape entries such as 12' 6 1/2" (in feet or inches). Prices are optional.
Key facts
load (lb/ft²) = depth (ft) × density; snow density = 14 ÷ (1 − 0.13 × depth), at most 30 lb/ft³ weight = load × footprint
Safety
If a roof sags, leaks or creaks under snow, get off it and call a professional. Roof design loads are set by local code from ASCE 7; a structural engineer can tell you your roof's capacity.
Questions
How much does a foot of snow on a 50 × 30 ft roof weigh?
About 24,138 lb (16.1 lb/ft²).
Formulas
load (lb/ft²) = depth (ft) × density; snow density = 14 ÷ (1 − 0.13 × depth), at most 30 lb/ft³ weight = load × footprint
Sources
Limitations
- Material densities are typical values (the midpoint of the commonly published range); real loads vary with moisture, grading and compaction, so check with your supplier or type in their density.
- Tank results are the geometric volume; real tanks have wall thickness and fittings.