What the calculator estimates
The calculator adds eave, rake, and valley lengths into a net edge run, then divides by effective piece length to estimate pieces, applying overlap and waste.
Plan gutter apron before you order coil
Enter eave and rake lengths, choose a profile, and the calculator works out linear feet, 10-foot pieces with overlap, and material cost. Real coverage changes with corners, valleys, and installer, so use this as a planning estimate.
BuildingSingle family home
ProfileDrip edge (Type C)
Waste factor10%
Roof edge dimensions
Enter total eave and rake lengths. For complex roofs, add valley lengths separately.
Profile and cost
Piece length is the stock coil or pre-cut length. Overlap is lost at each joint.
Drip edge vs gutter apron
Drip edge (Type C or D) protects the roof deck edge. A gutter apron is a wider flashing that extends behind the gutter. Building codes often require drip edge at the eaves and rakes.
Planning note
Real coverage changes with roof pitch, fascia size, corners, and installer. Confirm gauge, finish, stock length, and bundle quantity with your supplier.
Formula used
- Convert eave, rake, and valley lengths to feet.
- Net linear feet = eave + rake + valley.
- Apply waste factor to net linear feet.
- Effective piece length = piece length - overlap (in feet).
- Pieces = ceil(total linear feet with waste / effective piece length).
- Coverage = pieces x effective piece length / net linear feet.
How much drip edge do I need for my roof?
Add the total eave length, both rake lengths, and any valley length. Most building codes call for drip edge along the eaves and rakes, and you add about 10 percent for waste, overlap, and cuts. This calculator automates that total and divides it into stock pieces.
What is the difference between drip edge and gutter apron?
Drip edge is an L-shaped flashing nailed along the roof edge to direct water away from the fascia. A gutter apron is a wider profile that tucks behind the gutter so water cannot run behind it. Both are estimated the same way by total edge length.
How much overlap should gutter apron pieces have?
A 1 to 2 inch overlap per joint is common so water sheds over the seam. Shorter stock pieces create more joints and more overlap loss, which is why this calculator subtracts overlap before counting pieces.
Do I need drip edge on the rakes too?
Most modern codes require drip edge on both eaves and rakes for asphalt shingle roofs. The rake pieces run up the sloped edge, so include both rake lengths in your total run.
How much waste should I add?
A 10 percent waste factor covers cuts, corners, damaged pieces, and starter waste. Roofs with many hips, valleys, or dormers may need 15 percent, and simple rectangular roofs may need less.
Is this a contractor quote?
No. It is a planning estimate. Prices, gauge, finish, fasteners, underlayment, labor, delivery, taxes, and code requirements vary by supplier, product, roof, and location.