Span in, pitch chosen, ridge height appears fast. Includes angle, ratio, or percent slope options. Download clean CSV and PDF summaries for every project.
| Span (ft) | Pitch (rise:12) | Wall Height (ft) | Overhang (ft) | Ridge Above Wall (ft) | Total Ridge Elev. (ft) |
|---|---|---|---|---|---|
| 24 | 6:12 | 8 | 1 | 6 | 14 |
| 30 | 8:12 | 9 | 1 | 10 | 19 |
| 18 | 4:12 | 7.5 | 0.5 | 3 | 10.5 |
Ridge height is the vertical rise from the wall plate to the roof peak on a symmetric gable. It controls attic volume, ventilation pathways, and the roof’s visual proportion. On site, the “ridge rise” is computed from the half-span run and the roof slope.
The span (building width) drives run because run equals half the span. Pitch sets the slope, and wall height shifts the ridge elevation above finished floor. Overhang does not change ridge rise, but it does change fascia-to-ridge rafter length used for cut lists.
Common residential pitches often range from 4:12 to 8:12. A 6:12 slope means 6 units of rise for each 12 units of run, giving a slope of 0.5 and an angle near 26.6°. Steeper slopes improve runoff, but increase material and labor.
With a 24 ft span and 6:12 pitch, run is 12 ft and rise becomes 6 ft. If wall height is 8 ft, total ridge elevation becomes 14 ft. For a 30 ft span at 8:12, run is 15 ft and rise is 10 ft, producing a 19 ft total elevation with 9 ft walls.
Rafter length is the diagonal from the wall line to the ridge and is found with the Pythagorean relationship. For the 24 ft, 6:12 case, the rafter is √(12² + 6²) ≈ 13.42 ft. Adding a 1 ft overhang extends run to 13 ft and increases the fascia-to-ridge length accordingly.
Construction teams may work in feet, inches, or meters. This calculator keeps all inputs consistent by using a single unit selection and converts internally for stable math. When measuring spans, confirm whether you’re using outside-to-outside framing or the actual bearing line to avoid systematic offsets.
Compare ridge elevation against stair headroom, mechanical clearances, and neighborhood height limits. Small pitch changes can produce large height differences on wide buildings. For example, increasing pitch from 6:12 to 7:12 on a 30 ft span raises the ridge rise by 1.25 ft (15 × (7−6)/12).
Exported CSV and PDF outputs help document assumptions for estimating and permitting. Store span, pitch method, and results with your plan set so revisions stay traceable. Good records reduce rework, especially when truss orders and fascia details change late in the schedule.
No. Overhang extends the roof beyond the wall, but ridge rise is still based on half-span run at the wall line. Overhang only affects fascia-to-ridge rafter length and related material takeoffs.
Enter the horizontal distance between the two supporting wall bearing lines. If you measure outside-to-outside, subtract wall thickness if your bearing line is centered, or measure plate-to-plate for best accuracy.
Select “Rise per 12 run” and enter 6 as the pitch value. The calculator assumes the run reference is 12 units and converts that ratio to slope for all other outputs.
Yes. Choose the angle method and enter the roof angle from horizontal. The calculator uses the tangent of the angle to convert to a rise/run slope for ridge and rafter calculations.
Ridge elevation includes wall height plus ridge rise. If you only want the peak above the wall plate, use “Ridge height above wall plate.” Also verify unit selection and whether your span matches the actual bearing width.
No. Results are geometric based on span and slope. If you need structural detailing, add adjustments for ridge board depth, truss heel height, ceiling pitch offsets, and any raised-heel insulation requirements.
Use “Rafter length (fascia to ridge)” when you include overhang and want a field-friendly diagonal length. Use “Rafter length (wall line to ridge)” for basic framing geometry and checks against drawings.
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.