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Drip Edge Calculator

Drip edge is the L-shaped metal flashing along eaves and rakes. Required by current code; sometimes "value-engineered out" of bids. This calculator gets the right linear footage and 10-foot piece count for a complete order.

Edge measurements

Walk the perimeter of every roof slope's dripline. Add them up.
The angled edges of gables and dormers. Measured along the slope, not horizontally.
Each piece overlaps the next by 1–2″. Plus mitre cuts at corners.
Total drip edge needed248 LF
10-foot pieces25
Material cost range$275–$550
Drip edge is now code in most jurisdictions. Pre-2012 IRC didn't require it; current code does at all eaves and rakes. If your bid doesn't itemize drip edge, ask why — it's a $250–$400 line item that some bids "forget" to keep their headline number low.
Color and profile. Drip edge comes in mill-finish aluminum, white, brown, and color-matched options. Match it to your trim color, not your shingle — the drip edge is visible from the ground at the eave line.
→ Ice & Water Shield Calculator
I&W shield goes UNDER drip edge at eaves. The order is: deck → drip edge at eave (under) → I&W → underlayment → drip edge at rake (over).

What drip edge does

Drip edge is L-shaped metal trim that wraps the bottom edge of the roof deck. It does three things:

  1. Sheds water past the fascia — water flows off the shingles, hits the drip edge's lower flange, and falls clear of the wood fascia behind it.
  2. Protects the deck edge — wood deck edges absorb water and rot if nothing covers them.
  3. Provides a finished look — clean line at the eave instead of exposed deck or shingle bottoms.

Eaves vs rakes: install order matters

At the eaves (bottom edges), drip edge goes under the underlayment (and under any I&W shield). Water that gets past the shingles drains down the underlayment, onto the drip edge, and out.

At the rakes (sloped side edges), drip edge goes over the underlayment. Water blown sideways under the rake-edge shingles is shed off the drip edge instead of behind it.

A bid that doesn't differentiate "under at eaves, over at rakes" probably has a crew that doesn't either. Ask the question.

Profile sizes

  • D-style (most common) — 1.5″ face × 2.5″ deck flange. Standard for residential.
  • F-style — wider face (typically 3″) — used when fascia needs more coverage, or for older homes with non-standard trim.
  • T-style — for tile roofs; designed to interlock with starter tiles.

Color matching

Drip edge comes in mill-finish aluminum (silver), white, brown, and several specialty colors. Match it to your fascia trim color, not the shingle — drip edge is most visible from the ground at the eave line, where it sits next to the fascia and gutter.

About this calculator

Reviewed by Eurocraft, a Texas-licensed general contractor. Pricing per 10-foot piece reflects current South-region distributor cost.