Roof Step Flashing Calculator
Estimate individual step-flashing pieces for sloped roof-to-wall intersections using wall-run length, shingle exposure, wall count, kick-out pieces and package size.
Default project preview
1 boxes
Shingle courses per run
39
Field step-flashing pieces
78
Kick-out and starter pieces
4
Purchased pieces
100
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Sloped roof-wall length per run
Enter this project assumption in ft. The current imperial default is 18 ft.
Equal roof-wall runs
Enter this project assumption in a unitless value. The current imperial default is 2. Minimum: 1.
Shingle course exposure
Enter this project assumption in in. The current imperial default is 5.625 in.
Kick-out and starter pieces per run
Enter this project assumption in a unitless value. The current imperial default is 2. Minimum: 0.
Cuts and spare allowance
Enter this project assumption in %. The current imperial default is 10 %. Minimum: 0. Maximum: 50.
Step-flashing pieces per box
Enter this project assumption in a unitless value. The current imperial default is 100.
Price per box
Enter this project assumption in a unitless value. The current imperial default is 82. Minimum: 0.
How to read the outputs
Shingle courses per run
18 ft ÷ 5.63 in. Default preview: 39.
Field step-flashing pieces
one modeled piece per shingle course. Default preview: 78.
Kick-out and starter pieces
editable additions per run. Default preview: 4.
Purchased pieces
100 per box. Default preview: 100.
Extra purchased pieces
box rounding. Default preview: 9.
Flashing cost
full boxes only. Default preview: $82.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Pieces per run = roof-wall length ÷ shingle exposure, rounded up. Multiply by runs, add kick-out/starter pieces and waste, then round to full boxes.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Roof Step Flashing Calculator questions
Why is one piece modeled per shingle course?+
Step flashing is normally layered with successive shingle courses so water sheds over the piece below.
Is counterflashing included?+
No. Masonry and some wall systems need separate counterflashing or through-wall details.
Does the calculator specify flashing dimensions?+
No. Use dimensions and corrosion resistance required by the roof system, wall assembly and project details.