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Roof Truss Load Calculator

Dead, live, snow and wind load on a roof truss, with total roof weight.

Try an example:

Roof Span

Wall-to-wall width of the building

Building Length

Length along the ridge

Pitch Input Choose rise-per-12 or an exact angle

Roof Pitch Rise per 12" of run

Overhang

Eave overhang beyond the wall

Roof TypeChanges slope geometry and area

Min. Usable Ceiling Height (ft)Used for the usable attic/room width result

Material

Truss Spacing (in o.c.)

Your Price per Truss ($)Optional — leave 0 to estimate from lumber

Snow Load (psf)

Wind Load (psf)

Roof Height—

Rafter Length (with overhang)—

Rafter (no overhang)—

Roof Angle—

Rise—

Run—

Roof Area—

Truss Count—

Estimated Lumber—

Material Cost—

Cost per Truss—

Dead Load—

Live Load—

Snow Load—

Wind Load—

Total Weight—

Usable Room Width—

Estimate: $0

Material $0 · Labor $0 · Install $0

Include installation cost in total

Estimates only. Prices vary by region, supplier and site conditions.

Loads on a roof truss

Dead load: the permanent weight of trusses, sheathing, roofing and ceiling.
Live load: temporary loads such as workers and equipment; commonly 20 psf for roofs.
Snow load: from local ground snow data; it replaces the live load when higher.
Wind load: pressure and uplift that depends on exposure, height and shape.

design load = dead + max(live, snow); weight = design load × roof area

Use local code tables for snow and wind, not guesses. Read the load calculation guide for a worked example.