Roofing takeoff software
In short
The trap in roofing takeoff is that a plan shows the flat footprint, not the sloped surface — so measure each roof plane's plan area, then apply a pitch factor for the true covering area. Add ridge, hip, valley and eaves lengths for finishings. Solid Takeoff measures planes and edges on the PDF; you apply the pitch factor. Free to start.
Roofing is area work with a geometry twist. A roof plan gives the plan (flat) area; the actual surface you cover is larger because the roof is pitched. Skip the pitch adjustment and you'll under-order every time.
Measure each plane, apply the right factor for its pitch, then pick up the linear finishings — ridge, hips, valleys, eaves and verges — that a covering-only measure misses.
What you measure in a roofing takeoff
| Item | Unit | How you take it off |
|---|---|---|
| Roof covering area | m² | Plan area of each plane × pitch factor for the true sloped area. |
| Battens | m | Sloped area ÷ batten gauge (tile-dependent), or by run. |
| Ridge & hips | m | Measure ridge and hip lines as linear runs. |
| Valleys | m | Measure valley lines; add lap/cutting allowance. |
| Eaves, verges, fascia | m | Perimeter edges from each plane; fascia and soffit follow the eaves. |
| Tiles / slates | nr | Sloped area ÷ cover per unit, plus cutting waste. |
Plan area × pitch factor = real area
A roof plane's plan area understates the surface. Multiply by the pitch factor (1 ÷ cos of the pitch): about ×1.035 at 15°, ×1.155 at 30°, ×1.414 at 45°. Measure each plane's plan area in Solid Takeoff, apply the factor for its pitch, and keep mixed pitches in separate conditions so each gets the right factor.
Note the pitch on the drawing with a text label, or keep a condition per pitch, so the adjustment is auditable later.
The linear finishings add up
Ridge, hips, valleys, eaves and verges are all linear — measure them as runs (the perimeter of each plane gives you eaves and verges to start). They drive ridge tiles, hip irons, valley trays, dry-verge and fascia/soffit, and they're easy to forget when you're focused on area.
Cut-up roofs with lots of hips and valleys need more covering waste — bump the waste % on those.
Estimator's tips
- •Always apply the pitch factor — plan area alone under-reads the covering.
- •Pitch factor ≈ 1 ÷ cos(pitch): ×1.155 at 30°, ×1.414 at 45°.
- •Keep a condition per pitch so each plane gets the correct factor.
- •Ridge/hip/valley/eaves are linear — grab eaves and verges from plane perimeters.
- •More hips and valleys = more cutting; raise the covering waste on cut-up roofs.
Frequently asked questions
How do I measure roof area from a plan?
Measure each roof plane's plan (flat) area, then multiply by the pitch factor (1 ÷ cos of the pitch) to get the true sloped covering area. Solid Takeoff measures the planes; you apply the factor per pitch.
What is the roof pitch factor?
It converts flat plan area to sloped area: 1 ÷ cos(pitch angle) — roughly ×1.155 at 30° and ×1.414 at 45°. Apply it to each plane's plan area.
How do I measure ridge, hips and valleys?
As linear runs along those lines; the perimeter of each roof-plane area also gives you eaves and verges. These drive ridge tiles, hip irons, valley trays and fascia/soffit.
Is there free roofing takeoff software?
Yes — Solid Takeoff's free plan measures plane areas and edge lengths with export (watermarked on free); apply the pitch factor from the totals.
Try it on your own plan — free
Open a PDF and measure in your browser. No card, no install, no CAD. Free plan forever.