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Standard window sizes in India: a size chart in feet and millimetres

Commonly used sizes for sliding, casement, fixed, ventilator and kitchen windows, with sill heights, frame and opening sizes, 100 mm modules and the arithmetic to convert feet to mm and sq ft to sq m.
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THE SHORT ANSWER

Common sizes exist, a mandatory standard size does not

There is no mandatory standard window size in India. The commonly used sizes, width first, are 4 x 4 ft (1219 x 1219 mm) for a bedroom, 5 x 4 or 6 x 4 ft for a living room, 4 x 3 ft for a kitchen and 2 x 1.5 ft (610 x 457 mm) for a bathroom ventilator.
These come from Indian guides and retail schedules, not a code. Building rules set minimum opening area for light and ventilation; confirm the figure your architect or local authority uses. AluK Home windows are made to measure by certified AluK Home partners, so size to the room.

Common window sizes by room

Width first, then height. Millimetres are feet multiplied by 304.8, rounded to the nearest millimetre. Square metres are square feet multiplied by 0.0929.
Room or useSize W x H (ft)Size W x H (mm)Area (sq ft)Area (sq m)
Bedroom4 x 41219 x 1219161.49
Living room5 x 41524 x 1219201.86
Living room, larger6 x 41829 x 1219242.23
Kitchen4 x 31219 x 914121.11
Staircase4 x 21219 x 61080.74
Bathroom2 x 2610 x 61040.37
Bathroom or ventilator2 x 1.5610 x 45730.28

Commonly used sizes from Indian guides (Houseyog, Studio Matrx), not a standard. Conversions and areas: arithmetic.

Standard sliding window sizes

Sliding windows are usually described by their number of tracks as well as their size. These are the sizes that appear in Indian schedules and retail listings.
TypeSize W x H (ft)Size W x H (mm)Area (sq ft)Where it appears
2 track4 x 31219 x 91412Houseyog schedule
2 track5 x 3.51524 x 106717.5Houseyog schedule
3 track6 x 41829 x 121924Houseyog schedule and a retail 3 panel listing
4 track8 x 52438 x 152440Retail listing, orientation not stated

Commonly used market sizes, not a standard. Conversions and areas: arithmetic.

SLIDING VERSUS CASEMENT

Why a sliding window and a casement of the same size ventilate differently

Size on paper and opening area in use are different numbers. One Indian guide notes that a two panel sliding window opens about half its glazed area, because one panel parks behind the other, while a casement opens nearly all of its sash. In a small room with a ventilation figure to meet, that can decide the window type.

Helpful next reads: window types for Indian homes and glass thickness for windows.

Sliders suit openings where an outward sash is awkward, such as onto a balcony. AluK lists SC45 for 2, 3, 4 or 6 sash windows and patio doors, and SC95 for windows and balcony doors. See our aluminium sliding windows; for full-height glass, the standard sliding door sizes guide takes over.

Casement and fixed window sizes are set by the sash and the glass

The Indian guides we read give room sizes, not casement sizes, so the useful limit is the sash. A 4 x 4 ft window built as two side-hung sashes gives about 610 mm per sash before frame deductions, well inside the AluK figures below. See aluminium casement windows, and the concealed-sash AluK Infineo casement, which AluK Home describes as using 65 mm profiles.
Fixed windows have no common market size in the sources we checked. They are made to the opening and limited by the glass and frame system. For low fixed panes, see the safety glass note under sill heights, and the fixed aluminium windows page for uses.

AluK window sash sizes from published datasheets

Each figure is per sash, not per window. A window can be wider by adding sashes or fixed panes.
SystemTypeSash size W x H (mm)Glass
67IWSide-hung casementUp to 1400 x 1400Up to 60 mm
67IWTurn and tiltUp to 1500 x 1500Up to 60 mm
C87K-CS-NIOutward opening casement, single or double sash, or fixed800 x 1800 standard sashUp to 32 mm
SC45Sliding, 2, 3, 4 or 6 sashes1200 x 2800 standard sash (unit not stated)Up to 24 mm
Versatile casement rangeCasementNot stated5 to 40 mm

Sources: in.aluk.com datasheets (67IW, C87K-CS-NI, SC45) and the AluK Home India casement page (Versatile range). The datasheets do not define a standard sash as an absolute maximum; confirm per project.

VENTILATORS AND KITCHENS

Ventilator window sizes and kitchen windows

A ventilator is judged by its open area, so the square metre column matters most. Building rules set minimum opening area for light and ventilation; confirm the figure your architect or local authority uses, then check it against the opening part of the window.
Ventilator size W x H (ft)Size W x H (mm)Area (sq ft)Area (sq m)Where it appears
1.5 x 1.5457 x 4572.250.21Smallest size in one uPVC maker's range
2 x 1.5610 x 45730.28Indian guides, common bathroom size
2 x 2610 x 61040.37Indian guides, bathroom
4 x 51219 x 1524201.86Largest size in one uPVC maker's range

Range from Asian Paints Decorpro uPVC ventilators (1.5 x 1.5 ft to 5 ft high x 4 ft wide); other sizes from Houseyog and Studio Matrx. Commonly used sizes, not a standard. Areas: arithmetic.

Reading the ventilator chart

The two common ventilator sizes differ more than they look. A 2 x 1.5 ft unit is 0.28 sq m; a 2 x 2 ft unit is 0.37 sq m, about a third more. If part of the unit is a fixed pane or a fan panel, only the opening part counts towards ventilation. Our guide to bathroom ventilator windows in aluminium compares louvres, top-hung sashes and fans.
Kitchen windows are commonly 4 x 3 ft (1219 x 914 mm) and sit higher than room windows, so the sill clears the counter. Allow for the tap, the backsplash and whether the sash can open over the sink.

Window sill heights above the floor

Sill height is measured from the finished floor, so confirm the floor build-up before fixing it.
RoomSill above floor (ft)Sill above floor (mm)Source
Living room and bedroom2 to 2.5600 to 750Houseyog, Studio Matrx
Kitchen3.5 to 41050 to 1200Houseyog, Studio Matrx
Bathroom5About 1500Houseyog, Studio Matrx
Accessible windowAbout 1.5 to 2450 to 600Studio Matrx

Common practice in Indian guides, not a code requirement. Feet equivalents of the 450 and 600 mm figures: arithmetic.

LINTEL

Lintel height has no standard figure, but lintel depth has a rule of thumb

The guides we read give no standard lintel or window head height, so we do not quote one; your architect sets it with the door heights and the beam. One Indian guide gives a lintel depth rule of thumb of 1/12 to 1/10 of the clear span for light wall loads, and requires structural design above a 1.8 m span.
Low sills raise a separate point. A guide on glass in Indian homes says good practice expects safety glass within roughly 800 to 900 mm of the floor. Every living room and bedroom sill in the chart is lower, so ask what glass sits in the bottom pane.

Masonry opening, frame size and clear opening are three different numbers

The masonry opening is the hole in the wall. The frame size is the aluminium unit, a little smaller so it can be packed, fixed and sealed. The clear opening is what you see and pass through, smaller again.
The 1961 edition of IS 1948 gave aluminium window frame sizes after allowing 1.25 cm (12.5 mm) of clearance on all four sides of a modular opening. That is the older standard; it has been replaced by IS 1948:2024 and the current edition governs. On a real job the gap is the one on the fabricator’s drawing, and our guide to measuring for windows explains the method.
  • Masonry or structural opening: brick or concrete, edge to edge
  • Frame size: the opening minus the fitting gap on each side
  • Clear or daylight opening: the glass and airway you actually get

Modular 100 mm sizes and the 1961 fitting rule

The 1961 IS 1948 text designated a unit by the number of 10 cm modules in its width, a type letter, then the modules in its height. Its own example, a window 10 modules wide, has a 97.5 cm frame: 1000 mm less 12.5 mm each side.
ModulesModular opening (mm)Frame size, 1961 rule (mm)Opening in ft (approx.)
66005751.97
99008752.95
1010009753.28
12120011753.94
15150014754.92
18180017755.91

Arithmetic applying the 1961 clearance rule (frame = modular opening minus 25 mm). This is not the standard's own size table, and the 1961 edition has been replaced.

CONVERSIONS

Converting feet to mm, and sq ft to sq m

Multiply feet by 304.8 for millimetres and inches by 25.4. Multiply square feet by 0.0929 for square metres, or divide by 10.764. Round once, at the end. Seven feet is 2134 mm, not the 2200 mm some websites print.
FeetMillimetresMetres
1.54570.457
26100.610
2.57620.762
39140.914
3.510671.067
412191.219
515241.524
618291.829
721342.134

Arithmetic, 1 ft = 304.8 mm exactly. Example: a 12 x 12 ft room is 144 sq ft, which is 13.38 sq m.

Four checks before you fix a window size

Measure the opening, not the catalogue

A 4 x 4 ft window is a habit, not a rule. Start from the room, the wall and the view, then measure the actual opening at three points each way. The size that goes to the factory is the one on the signed drawing.

Say which number is the width

Some Indian schedules write windows width first and doors height first. Write W x H with the unit on every sketch, and convert from the measured figure, never from a rounded one. That removes the most common ordering mistake.

Check the open area, not the glass area

If your architect gives a minimum opening area for a room, compare it with the part that opens. A two panel slider opens about half its glass, a casement nearly all. The type of window can change whether a size meets the figure.

Ask about glass near the floor

Sills of 600 to 750 mm put the bottom pane well inside the zone where one guide says safety glass is expected. Ask what that pane is made of and see a sample before ordering. Changing it after fabrication means new glass.

FAQ

Window size questions

Short answers, with the source type and the limits stated.
There is no single mandatory size. Indian guides commonly use 4 x 4 ft (1219 x 1219 mm) for bedrooms, 5 x 4 or 6 x 4 ft for living rooms, 4 x 3 ft for kitchens and 2 x 1.5 ft for bathroom ventilators. Size the window to the room and the light and ventilation figure your architect or local authority applies.
4 x 4 ft, which is 1219 x 1219 mm or 1.49 sq m, appears in both Indian guides we read. A larger bedroom may need more. Check the opening area against the ventilation figure your architect uses, remembering that a sliding window opens only part of its glass.
Indian guides give 2 x 1.5 ft (610 x 457 mm) or 2 x 2 ft (610 x 610 mm), with the sill at about 5 ft. One uPVC maker sells ventilators from 1.5 x 1.5 ft up to 5 ft high by 4 ft wide. A 2 x 2 ft unit has about a third more area than 2 x 1.5 ft.
An Indian schedule lists two track sliding windows at 4 x 3 ft or 5 x 3.5 ft and three track windows at 6 x 4 ft (1829 x 1219 mm). Retail listings show four track units at 8 x 5 ft. These are commonly used sizes; made-to-measure systems are limited per sash instead.
There is no Indian standard maximum. The limit is the sash size of the system, and a window gets wider by adding sashes and tracks. AluK SC45 lists a standard sash of 1200 x 2800 (unit not stated) with up to 6 sashes, and SC95 1500 x 3500 mm. Neither is defined as an absolute limit, so confirm per opening.
Indian guides put living room and bedroom sills at 2 to 2.5 ft (600 to 750 mm), kitchen sills at 3.5 to 4 ft (1050 to 1200 mm) and bathroom sills at about 5 ft (1500 mm). An accessible window may sit at 450 to 600 mm. Measure from the finished floor.
Building rules set minimum opening area for light and ventilation, usually linked to floor area. The secondary summaries we read quote different figures and none gave the primary text, so we do not repeat one. Confirm the figure your architect or local authority uses, then check it against the opening part of the window.

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