Door and Window Schedule Calculator
Opening area, glass area, profile length and weight.
Quick answer
With the default inputs: Opening width 1.5 m · Opening height 2.1 m · Count 20 sets etc.Total opening area 63.00 m²
Edit the inputs below to recalculate.Inputs
Result
Total opening area
63.00m²
| Opening area per unit | 3.150m² |
| Total opening area | 63.00m² |
| Glass size per unit | 1.380 × 1.980m |
| Glass area per unit | 2.732m² |
| Total glass area | 54.65m² |
| Glass weight | 819.7kg |
| Total profile length | 144.0m |
| Profile weight (frame only) | 259.2kg |
| Profile per m² of opening | 4.11kg/m² |
| Glass to opening ratio | 86.7% |
Doors and windows are measured by opening area, not frame outer area — the billed area is opening width × height and includes the frame. Glass must deduct the frame: net size = opening − 2 × frame width, and in practice seals and clearances too. Glass weight is 2.5 kg/(m²·mm): 6 mm single is about 15 kg/m², 5+9A+5 double about 25 kg/m² (enter 2 panes). Profile here is the outer frame perimeter only, without mullions, sashes and beads, hence about 4 kg/m²; a complete thermal-break window runs 8-12 kg/m², so use that rate for costing.
Formula
| Opening per unit | A = width × height |
| Total opening | A = A × count |
| Net glass size | b = width − 2 × frame; h = height − 2 × frame |
| Glass area | A = b × h × count |
| Glass weight | G = A × thickness × 2.5 × panes |
| Profile length | L = 2 × (width + height) × count |
Twenty 1500×2100 openings with 60 mm frames, 6 mm single glazing and 1.8 kg/m profile: 3.150 m² each, 63.00 m² total; glass 1.380×1.980 m, 54.65 m² weighing 819.7 kg; 144.0 m of profile weighing 259.2 kg.
FAQ
Why measure openings rather than frame outer area?
Because that is the billed basis. Opening sizes are shown on drawings and can be checked on site, while frame outer sizes vary with the profile series. The opening area also bundles frame, gap sealing and sealant so nothing is missed, and suppliers quote on the same basis with profile, glass, ironmongery and installation included. So quantity = width × height × count — do not deduct the frame yourself.
Why 2.5 kg per square metre per millimetre?
Flat glass is about 2500 kg/m³, so 1 m² at 1 mm is 0.001 m³ and weighs 2.5 kg. Hence 5 mm is 12.5 kg/m², 6 mm 15, 8 mm 20, 12 mm 30. Double glazing is two panes plus a gas gap: 5+9A+5 is about 25 kg/m², with the gas layer contributing nothing. This figure drives lifting, transport and structural load, and on large panels it decides suction-cup count and the lifting method.
How do I estimate profile usage reliably?
Use a per-square-metre rate for the whole window, not the outer perimeter. Thermal-break aluminium runs 8-12 kg/m² including frame, sashes, mullions and beads; standard aluminium sliding 7-10; uPVC 5-7. It depends on type (fixed is leanest, casements add sash profile, sliders add track), number of divisions, the profile series and whether there is a screen. Ask the fabricator for the rate for that window type — this tool only measures the outer frame line.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.