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Door and Window Schedule Calculator

Opening area, glass area, profile length and weight.

Quick answer

With the default inputs: Opening width 1.5 · Opening height 2.1 · Count 20 sets etc.Total opening area 63.00 m²

Edit the inputs below to recalculate.
Length LHeight HThickness T
Opening area is width × height including the frame; glass area deducts the frame width.

Inputs

sets
Aluminium frames are usually 50-70 mm wide
5-6 mm single; double glazing counts both panes
pcs
kg/m
Thermal-break aluminium 1.5-2.2 kg/m

Result

Total opening area
63.00m²
Opening area per unit3.150m²
Total opening area63.00m²
Glass size per unit1.380 × 1.980m
Glass area per unit2.732m²
Total glass area54.65m²
Glass weight819.7kg
Total profile length144.0m
Profile weight (frame only)259.2kg
Profile per m² of opening4.11kg/m²
Glass to opening ratio86.7%

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 unitA = width × height
Total openingA = A × count
Net glass sizeb = width − 2 × frame; h = height − 2 × frame
Glass areaA = b × h × count
Glass weightG = A × thickness × 2.5 × panes
Profile lengthL = 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.

How to work it out

  1. Count by opening first: width × height × quantity = opening area. Schedules and payment are measured on the structural opening, always.
  2. Glass area: glass size = (opening width − 2 × frame width) × (opening height − 2 × frame width − transom depth). With 60 mm frames a 1.5 × 2.1 opening gives roughly 1.35 × 1.95 of glass.
  3. Count insulating units by panes: a double-glazed unit is the sum of two glass areas; Low-E and laminated follow the same logic.
  4. Profile length: perimeter per opening × quantity, then multiplied by weight per metre. Thermal-break aluminium runs 1.8-2.5 kg/m, plain aluminium 1.5-2.0.
  5. Add ironmongery: hinges, handles, locks and friction stays per opening; gaskets by perimeter; foam by opening perimeter × joint width.

Where it goes wrong

Material and cost

Thermal-break aluminium 600-1200 CNY/m² with glass and installation, plain aluminium 300-600, uPVC 250-450. Double-glazed Low-E adds 100-200 per m². Fire-rated windows cost two to three times standard.

On site

Basis

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.

Cite this page

Use this format in reports, method statements or coursework. The link is permanent.

Building Calculator. Door and Window Schedule Calculator. 2026-10-25. https://jianzhujisuan.com/en/door-window-schedule

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.