Linear Feet Calculator for Roofing
While shingles are sold by the square (100 sq ft), most roofing trim — starter strips, ridge caps, drip edge, and valley flashing — is sold by the linear foot. This calculator helps you estimate the linear footage of all roof edges.
Linear Feet for Roofing
Calculate linear feet for roofing
Select your roof type and enter the dimensions of each edge. This calculator sums up all edges where trim materials are needed.
Measured along the bottom of the roof
Measured along the angled side
The horizontal peak
Total of all hips and valleys (0 for gable)
Roof Trim Materials Measured in Linear Feet
| Trim Material | Where It Goes | Typical Unit |
|---|---|---|
| Drip Edge | Along eaves and rakes to prevent water damage | 10-foot lengths |
| Starter Strip | First row along eaves, seals edge against wind | Roll or 36" strips |
| Ridge Cap | Along ridges and hips, covers the peak | ~35 LF per bundle |
| Valley Flashing | Where two roof planes meet at an inside corner | 10-foot lengths |
| Rake Edge | Along the sloped gable ends | 10-foot lengths |
How Roofers Calculate Linear Edge Materials
The total linear footage of roof trim is the sum of all edges. Here's what professional roofers measure:
- Drip edge goes on every eave and rake — that's the full perimeter of each roof plane. On a gable roof, LF = (2 × eave length) + (2 × rake length).
- Starter strip only goes on the eaves (bottom edges), not the rakes. One row of starter shingles seals the first course.
- Ridge cap covers the peak. On a hip roof, each hip line also needs ridge cap, so the total is ridge + all hips.
- Valley flashing runs the full length of each valley. If a valley is 16 feet long, you need a 16-foot piece of metal flashing (plus a few inches of overlap).
Always add 10% for waste, overlaps, and cuts. Standard drip edge and valley flashing come in 10-foot lengths, so round quantities up.