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Drip Edge Calculator
Calculate the exact number of 10-foot pieces and total linear footage of drip edge flashing needed for roof eaves and gable rakes, accounting for 2-inch laps and corner miters under IRC Section R905.2.8.5.
Calculates True AreaFactors in PitchIncludes Waste FactorSquares & Bundles
Example preview
Result21 Pieces (10-ft Sticks)
- Eave Drip Edge
- 13 pieces (126 LF)
- Rake Drip Edge
- 9 pieces (84 LF)
- Total Perimeter Measured
- 200 linear ft
- Total Linear Ft with Overlap
- 210 linear ft
- Fastener Requirement
- ~231 nails
- Building Code Mandate
- IRC Section R905.2.8.5
Enter your values and press Calculate to see your result.
How the Drip Edge Calculator Works
Follow the exact steps to get your result instantly and privately.
Step 1: Measure Total Eave Length
Sum all horizontal gutter edges where drip edge directs runoff away from fascia boards.
Step 2: Measure Total Rake Length
Sum all diagonal sloped edges along gable roof ends.
Step 3: Add Lap & Waste Factor
Apply 5% to 10% to account for mandatory 2-inch end laps, corner cuts, and gable peak wraps.
STEP 1
Step 1: Measure Total Eave Length
Sum all horizontal gutter edges where drip edge directs runoff away from fascia boards.
Drip Edge Piece & Linear Foot Formula
Drip edge is sold in rigid 10-foot metal pieces (aluminum, galvanized steel, or copper). IRC Section R905.2.8.5 dictates: 'A drip edge shall be provided at eaves and gables of shingle roofs. Adjacent segments of drip edge shall overlap a minimum of 2 inches (51 mm).' To calculate the required piece count, add 5% to your total perimeter to cover the 2-inch laps, then divide by 10 and round up to the next full piece.
Measuring Methods
- Eave Installation (Under Underlayment): Along eaves, drip edge is fastened directly to the wood decking before installing ice and water shield or underlayment.
- Rake Installation (Over Underlayment): Along gable rakes, underlayment is laid down first, and drip edge is installed over the underlayment to protect against wind-driven rain.
Total Linear Ft = (Eave Length + Rake Length) × (1 + Overlap Factor)
Total 10-ft Pieces = Ceiling(Total Linear Ft / 10)Example
For a home with 130 linear feet of eaves and 90 linear feet of rakes: Total perimeter = 220 LF. With a 5% overlap allowance: 220 × 1.05 = 231 LF. Divided by 10 ft: 231 ÷ 10 = 23.1 → 24 pieces of 10-foot drip edge needed (14 for eaves, 10 for rakes).
Worked examples
Review these common residential roof perimeter examples showing piece breakdowns between eaves and rakes.
| Scenario | Calculation | Result |
|---|---|---|
| Small Ranch (100 LF Eaves, 60 LF Rakes) | (100 LF + 60 LF) × 1.05 = 168 LF ÷ 10 | 17 Pieces (11 Eave, 7 Rake) |
| Standard Two-Story Colonial (140 LF Eaves, 80 LF Rakes) | (140 LF + 80 LF) × 1.05 = 231 LF ÷ 10 | 24 Pieces (15 Eave, 9 Rake) |
| Four-Sided Hip Roof (180 LF Eaves, 0 LF Rakes) | 180 LF × 1.05 = 189 LF ÷ 10 (Hip roofs have no rakes) | 19 Pieces (All Eaves) |
| Complex Gable with Dormers (160 LF Eaves, 130 LF Rakes) | (160 LF + 130 LF) × 1.10 (high waste) = 319 LF ÷ 10 | 32 Pieces (18 Eave, 15 Rake) |
Conversion reference
Quick reference table showing typical drip edge piece counts required for standard residential perimeter sizes.
| Total Perimeter | Linear Ft with 5% Lap | Eave Pieces (Approx) | Rake Pieces (Approx) | Total 10-ft Pieces |
|---|---|---|---|---|
| 100 LF | 105 LF | 6 pieces | 5 pieces | 11 pieces |
| 150 LF | 158 LF | 10 pieces | 6 pieces | 16 pieces |
| 200 LF | 210 LF | 13 pieces | 8 pieces | 21 pieces |
| 250 LF | 263 LF | 16 pieces | 11 pieces | 27 pieces |
| 300 LF | 315 LF | 19 pieces | 13 pieces | 32 pieces |
| 350 LF | 368 LF | 22 pieces | 15 pieces | 37 pieces |
| 400 LF | 420 LF | 25 pieces | 17 pieces | 42 pieces |
DID YOU KNOW?
Quick facts
- Drip edge became mandatory on all eaves and gable rakes under IRC Section R905.2.8.5 starting in the 2012 code cycle.
- A standard 10-foot drip edge stick only covers about 9 feet 10 inches of roofline because code requires a 2-inch overlap at every joint.
- Drip edge must extend at least 1/4 to 3/8 inch past the fascia board edge to create a capillary break that prevents rainwater from running down wall siding.
- Nails securing drip edge must be spaced a maximum of 12 inches on-center in a staggered zigzag pattern to prevent wind flutter.
C.R. Vance, PE
Senior Structural & Building Envelope Engineer
- Professional Engineer (PE)
- ICC Certified Building Inspector
- NRCA Technical Consultant
C.R. Vance has spent over 22 years evaluating residential roof assemblies, structural load calculations, and building envelope waterproofing compliance across North America.
Sources & references
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Got Questions?
Frequently Asked Questions
Clear answers about roof square footage calculations, pitch slope factors, shingle bundles, and ordering materials.
Add the total linear footage of all eaves (gutter lines) and all rakes (gable diagonal edges), multiply by 1.05 to account for mandatory 2-inch laps, and divide by 10. For example, a roof with 120 ft of eaves and 80 ft of rakes has 200 ft of perimeter, requiring 21 ten-foot pieces.
Yes. Under International Residential Code (IRC) Section R905.2.8.5, drip edge is legally required at all eaves and gable rakes of asphalt shingle roofs. Omitting drip edge will cause a building inspection failure in jurisdictions adhering to modern IRC/IBC standards.
At the eaves, drip edge is fastened directly to the roof decking before the underlayment or ice and water shield is rolled out (underlayment goes OVER eave metal). At the gable rakes, underlayment is applied first, and the drip edge is fastened over the top of the underlayment (rake metal goes OVER underlayment).
IRC Section R905.2.8.5 requires adjacent drip edge pieces to overlap by a minimum of 2 inches (51 mm). Always overlap in the direction of water flow (the piece higher up the slope overlaps over the piece lower down) to ensure water sheds cleanly.
T-Style (or D-Style / Deluxe) drip edge has an extended horizontal flange and a kick-out bend that directs water directly into the center of the gutter. F-Style features an extended downward vertical leg that fits behind gutters or over fascia boards. T-style is preferred for shingle installations.
At an outside corner where an eave meets a rake, do not butt-join two separate pieces. Instead, cut the vertical face of the eave drip edge, bend the top horizontal flange 90 degrees around the corner onto the rake by 2 to 3 inches, and lap the rake piece over it.
Use 1-1/4 inch hot-dipped galvanized roofing nails. Fasten nails every 8 to 12 inches on-center in a staggered pattern (one nail near the top edge, the next near the center), keeping fasteners at least 1 inch away from the outer edge to prevent splitting.
No. Reusing old drip edge is considered substandard roofing practice. Prying up old shingles damages the metal flanges, causes nail-hole tears, and ruins the seal between the metal and new ice and water shield. Drip edge should always be replaced during a tear-off.
Standard residential aluminum drip edge is typically 0.019 to 0.024 inch thick. Galvanized steel drip edge is typically 28 to 30 gauge (with G90 corrosion coating). In high-wind hurricane zones, heavy 26-gauge steel or 0.032 aluminum is recommended.
No. Hip roofs slope down on all four sides to gutter eaves and do not have gable ends or rakes. On a true hip roof, you only need to measure and purchase drip edge for the eave perimeters.
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