Snow Load Deck Calculator

Know how much winter weight your deck bears. Use flexible units and adjustment factors quickly. Save results as CSV or PDF for sharing later.

Calculator inputs

Choose a method, set dimensions, and adjust factors for your site. Results update after you submit.

The calculator shows both unit systems in results.
Use design load when code values are known.
Used to compute load per post.
ft
ft
lb
Adds utilization % when provided.
in
Depth of settled snow on the deck.
pcf
Typical range: 10–30 pcf (dry→wet).
psf
Enter code or site design pressure.
Open sites can drift more.
Raise for critical or crowded spaces.
Use >1.0 near walls, parapets, hedges.
Flat decks are usually near 1.0.
Cold decks can hold snow longer.
Adds a margin beyond adjusted load.
Reset

Formula used

Method A — Depth + Density
Base pressure is computed from snow depth and density.

  • Imperial: Base (psf) = (Depthft) × Densitypcf
  • Metric: Base (kPa) = (ρ × g × Depthm) ÷ 1000

Method B — Design Snow Load
Use a known design pressure directly as the base value.

Adjustments and Design Margin

  • Adjusted pressure = Base × Exposure × Importance × Drift × Slope × Thermal
  • Design pressure = Adjusted pressure × Safety factor
  • Total design load = Design pressure × Deck area
  • Load per post = Total design load ÷ Number of posts

How to use this calculator

  1. Select your unit system for measurements and loads.
  2. Choose a method: depth+density or a known design load.
  3. Enter deck length, width, and support post count.
  4. Adjust factors to match wind exposure, drift, and use importance.
  5. Click Calculate to view results above the form.
  6. Download CSV or PDF to save your project notes.

Example data table

Scenario Deck size Method Snow input Factors (E·I·D·S·T) Safety Posts Design pressure Total design load
Light snow 12×10 ft Depth+density 6 in, 10 pcf 1.0·1.0·1.0·1.0·1.0 1.2 6 6.00 psf 864 lb
Wet snow 4×3 m Depth+density 25 cm, 250 kg/m³ 1.1·1.0·1.2·1.0·1.0 1.3 8 1.07 kPa 12.84 kN
Code value 16×12 ft Design load 35 psf 1.0·1.1·1.3·1.0·1.0 1.2 8 60.06 psf 11,529 lb
Table values are examples for learning and comparison.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.