Top chord length
13.42 ft
Free truss geometry calculator
Roof Truss Calculator
Estimate basic roof truss geometry including top chord, bottom chord, truss height, pitch, overhang, and roof area per truss bay.
Truss geometry planning
Roof truss inputs
Span, pitch, height
Calculation mode
Quick examples
Top chord with overhang
15.65 ft
Bottom chord length
24 ft
Truss height
6.75 ft
Roof angle
26.57 deg
Roof area per truss bay
62.6 sq ft
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What this roof truss calculator does
This calculator estimates the basic geometry of a simple roof truss, including span, rise, top chord length, bottom chord length, overhang, total truss height, and roof area carried by one truss bay at the selected spacing. It is useful for early framing layouts, material planning, and simple geometry checks before ordering or reviewing truss drawings.
What it does not replace
Roof trusses are engineered structural components. Final web layout, connector plates, chord sizes, bearing requirements, heel details, uplift, live load, dead load, and bracing requirements should come from an engineered truss design or supplier drawing. This tool is meant for practical geometry and planning, not structural certification.
How the geometry works
For a symmetrical common truss, the full span is split into two equal runs. The roof pitch or roof angle determines the rise from the bearing line to the peak. The top chord is the sloped member from the peak down to the heel, and the bottom chord is the horizontal span between bearings. If an overhang is added, the top chord extension continues on the same slope past the wall line.
Planning note
Use inside or design dimensions consistently, and verify whether the heel height shown on your truss drawings is measured at the outside bearing or another reference point. If you are comparing this estimate to supplier drawings, always defer to the truss layout provided by the fabricator or engineer.