Visualize roof geometry instantly for any span and pitch. Customize units, slopes, overhangs, and heel heights with ease. Advanced options handle attic spaces, variable chords, and regulations. Export calculations, share reports, optimize materials and labor. Precision truss planning for builders, engineers, designers, and homeowners.
These sample values assume no raised heel and pitch given as X in 12.
| Span (ft) | Pitch (in 12) | Run (ft) | Approx. truss height (ft) |
|---|---|---|---|
| 20 | 4 | 10.00 | 3.33 |
| 24 | 6 | 12.00 | 6.00 |
| 30 | 8 | 15.00 | 10.00 |
For a symmetrical gable roof, the building span is divided by two to get the run: run = span / 2.
The slope depends on the chosen pitch definition:
Vertical rise from plate to ridge: rise = run × slope.
If a raised heel is used, total truss height becomes: truss height = heel height + rise.
Rafter length without overhang: rafter = √(run² + rise²). With overhang: rafteroverhang = √((run + overhang)² + rise²).
Always confirm with local codes, manufacturer data, and an engineer for structural design.
This tool is intended for preliminary geometric sizing only. Structural capacity, bracing, loading, spacing, and connection design must be verified by qualified professionals.
Shallow roofs (3:12–4:12) often suit simple garages and sheds. Moderate roofs (5:12–8:12) dominate residential projects with attics. Steeper roofs (9:12 and above) increase truss height, snow shedding, and attic usability at the cost of additional materials and labor.
For spans under 24 ft, moderate pitches usually keep heights manageable. Between 24–40 ft, heel height and overhang significantly affect building elevation. Long-span or attic trusses demand careful review of bearing, bracing, and transport limitations before committing to total truss height.
The calculator links span, pitch type, heel height, and overhang into one geometric model. It outputs run, rise, total truss height, and rafter lengths so designers validate elevations, fascia lines, attic clearance, and compatibility with local planning constraints.
Adjusting overhang length alters fascia and soffit alignment, shading, and water protection. Heel height changes insulation depth, eave line, and visible elevation. Reviewing these outputs helps match drawings, gutter positions, daylighting, and energy goals without guesswork onsite.
Designers working across regions can toggle units while keeping geometry consistent. The calculator preserves pitch and proportions as units change, simplifying coordination between international suppliers, fabrication shops, and site crews using different measuring standards on shared projects.
Many jurisdictions cap overall ridge elevation relative to boundaries or street levels. Use the calculated truss height with wall and foundation dimensions to verify compliance early, reducing redesign risk and helping planners visualize bulk, overshadowing, and neighborhood compatibility.
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.