Work out truss member force instantly with clear inputs, formula shown and shareable results.
For a simple triangular truss with load applied at the apex, each support carries half the load. Resolving at the support, the rafter force is the reaction multiplied by the rafter length divided by the rise, and the bottom tie force is the reaction multiplied by the half span divided by the rise. A flatter truss therefore has much larger member forces for the same load.
Member forces
Rafter = R x rafter length / rise; tie = R x (span/2) / rise, with R = load / 2
Preliminary estimate only. Truss analysis and member design must be carried out by a qualified structural engineer including wind uplift, buckling and connection design.
Rafter = R x rafter length / rise; tie = R x (span/2) / rise, with R = load / 2. For a simple triangular truss with load applied at the apex, each support carries half the load.
The rise is the lever arm resisting the applied moment. Halving the rise doubles both chord forces, which is why low-pitch trusses need much heavier chords.
This calculator takes 3 inputs: Truss span, Truss rise at apex, Total load on the truss. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.