Global Settings
in
Added once for every flashed corner joint.
%
ft
$
Openings
| # | Label | Width (in or mm) | Height (in or mm) | Sill | Left jamb | Right jamb | Head | Qty |
|---|
Tip: Press
Enter inside a cell to tab forward quickly.
Results
| # | Label | Sides flashed | Base length | Corner joints | Overlap added | Layers | Waste% | Total length |
|---|---|---|---|---|---|---|---|---|
| Project total length | — | |||||||
| Estimated rolls required | — | |||||||
| Estimated material cost | — | |||||||
Totals display in ft and also show metric equivalence.
Example Data
Use the button above to auto-load rows. This table simply illustrates typical entries.
| Label | Width | Height | Sill | Left jamb | Right jamb | Head | Qty |
|---|---|---|---|---|---|---|---|
| Bedroom Window | 48 in | 42 in | Yes | Yes | Yes | Yes | 2 |
| Kitchen Window | 36 in | 36 in | Yes | Yes | Yes | Yes | 1 |
| Patio Door | 72 in | 80 in | Yes | Yes | Yes | Yes | 1 |
Formulas Used
Per opening base length equals the sum of selected sides, multiplied by layers:
Base = (Sill?W:0) + (Head?W:0) + (Left?H:0) + (Right?H:0) LayersApplied = Base × Layers
Corner joints are counted where two selected sides meet. Each joint adds the specified overlap once, per layer:
OverlapAdded = CornerJoints × Overlap × Layers
Waste/contingency is added multiplicatively:
OpeningTotal = (LayersApplied + OverlapAdded) × (1 + Waste%/100)
Project total is the sum across openings multiplied by quantity per opening.
Rolls needed are rounded up:
Rolls = ceil(ProjectTotal ÷ RollLength)
How to Use
- Set Units, Corner overlap, Layers, Waste, and Roll length.
- Add rows for each opening with width, height, sides to flash, and quantity.
- Click Calculate to populate the results table and totals.
- Use Export CSV or Export PDF to download a summary.
- Adjust settings to see the impact on rolls required and cost.
Frequently Asked Questions
Many installers use about 6 in (150 mm) at each corner. Follow manufacturer requirements and local details; increase overlap in rough conditions or for redundancy.
Length is independent of width. Width is selected to suit opening size, material transitions, and detailing standards. This tool estimates length only and roll counts.
Practices vary. Sills and jambs are nearly universal; heads are commonly flashed, especially in wet climates. Follow project specifications, codes, and manufacturer details.
Typical contingency is 5–15% to account for cuts, rework, and site variability. Increase for complex openings, learning crews, or cold-weather applications.
A joint exists wherever two selected sides meet: sill–left, sill–right, head–left, head–right. If a side is not flashed, its adjacent corner doesn’t add overlap.
Yes. Increase Layers to apply multiple passes. Overlap is applied per layer as well, which increases total length and rolls required.
The tool divides the project total by the roll length and rounds up to whole rolls. If you enter a price per roll, it estimates material cost accordingly.
Choose a single unit system in Global Settings. Convert any mixed measurements as needed before entry to maintain consistent results and roll counts.
Length estimates remain the same. However, cold temperatures and rough substrates can increase waste. Adjust the waste percentage to reflect site realities and crew experience.
Model pre-formed corners by increasing corner overlap or adding small “openings” representing components. End laps along long pieces can be added as extra overlap length.