An opening area can help with deductions or an area based quotation. A frame length answers another question. The Whatson Door & Window Area Calculator gives both, using the dimensions and counts in your schedule.
Before measuring, decide whether the dimensions represent the rough opening, the finished opening or a product size. Use one basis consistently; these are not interchangeable in procurement.
Doors and windows use different frame models
Every row takes width, height and quantity in the selected measurement unit. Area is width × height × quantity.
A door frame is modelled with two jambs and a head, so its run is 2 × height + width. A window frame includes all four edges, giving 2 × (height + width).
Door thresholds are not included in the frame run. Window mullions and transoms are not added. Selecting door or window changes the perimeter model, not the area calculation.
One door and two windows
Enter one 3 × 7 ft door and two 4 × 4 ft windows.
| Scheduled item | Opening area | Model frame run |
|---|---|---|
| One door | 21 sq ft | 17 ft |
| Two windows | 32 sq ft | 32 ft |
| Total | 53 sq ft | 49 ft |
These are the checked calculator results. The 53 sq ft figure can support an area deduction, while 49 ft records the simplified frame edges.
Do not reuse every opening total everywhere
A brick estimate for one wall should deduct only the openings in that wall. The total for an entire house may be valid in this schedule but wrong as a deduction for a single face.
Similarly, a window opening area is not necessarily the glass area. Frame members, subdivisions and clearances can reduce or change the product quantity. This tool does not produce a glass cutting list or a joinery fabrication schedule.
Give repeated sizes one useful reference
A row such as “Bedroom windows, 4 × 4 ft, quantity 2” is easier to audit than two anonymous entries. Use separate rows when width, height or the measurement basis differs.
The cost rate is PKR per sq ft of opening area. It applies one shared rate to all scheduled openings. Doors and windows with different specifications and rates need separate calculations or their own budget lines.
Use the Brick Calculator or Paint Calculator for the material estimate after deciding which of these openings belongs to that measured surface. Carry across the area, not the frame length.