Framing tool
Roof Truss Calculator
Enter your building dimensions and spacing to get truss count, total span load, and an installed cost range for the truss package.
Truss count equals building length in inches divided by the on-centre spacing, plus one for the closing truss. A 40 ft building at 24 inches on centre needs 21 trusses. Common trusses run $75 to $400 each depending on span.
Calculate truss count
Spacing of 24 inches on centre is standard for engineered trusses.
Trusses needed
21
including the closing truss
Truss cost by span
Truss pricing scales with span and with the amount of engineered lumber in the webbing. A 24 ft common truss runs roughly $120 to $180; a 40 ft truss can exceed $400 because the chords get deeper and the plates larger. Attic and scissor trusses cost 40% to 80% more than a common truss of the same span.
Delivery and crane time are separate and easy to underestimate. Trusses over about 30 ft usually need a crane, which adds $500 to $1,500 for a typical residential set.
Trusses or stick framing
Trusses go up in a day where stick framing takes a week, they span further without interior bearing walls, and they arrive engineered to your snow and wind loads. That is why nearly all new residential construction uses them.
The trade-off is the attic. Webbing fills the space, so you lose usable storage and any possibility of a future room conversion unless you specify attic trusses up front. You also cannot cut a truss member, ever, without an engineer signing off on the repair.