Snow Load Calculator

Wet snow is the dangerous one

Fresh powder is around 70 kg/m³; settled snow 200; wet snow 400 and ice 900. Thirty centimetres of powder on a 100 m² roof is about 2 tonnes, while the same depth of wet snow is over 12 tonnes. This is why roofs fail during a thaw or after rain falls onto lying snow, not during the snowfall itself.

This is an estimate, not a structural assessment

Whether your roof can carry the load depends on its design, span, condition and local code minimums. If the number here is close to anything you are unsure about, get a structural engineer to look — not a calculator.

What this page needs from you

This page asks for roof area in m², snow depth in cm and snow type. From those it returns total load on the roof in kg. Every figure updates as you type, and nothing you enter leaves your browser.

Running short costs more than over-ordering

A second delivery carries its own charge, materials from a different batch may not match, and a job halted halfway often has to be redone at the join. Ordering slightly long is cheap insurance against all three.

Measure twice, and allow for waste

A 5% error on one dimension becomes 10% on an area and 15% on a volume, which is why checking the tape matters more than the arithmetic. On top of the measured quantity, allow the trade standard of 10% for cuts and breakage, and 15 to 20% for diagonal layouts, complex shapes or anything cut around obstacles.