How much flooring do I need for a 30x40 room?

Buy about 1,320 sq ft: the 1,200 sq ft floor plus 10% for cuts and waste. With boxes that cover 20 sq ft, that's 66 boxes. Diagonal or herringbone layouts need 15–20% extra instead.

How much paint do I need for a 30x40 room?

With 8 ft ceilings, one door and one window, the walls are about 1,084 sq ft. Two coats at 350 sq ft per gallon is 6.2 gallons, so buy 7. Painting the ceiling as well brings it to 13.1 gallons.

How many square meters is 30 by 40 feet?

111.48 m². The room is 9.14 m by 12.19 m.

How many sheets of drywall for a 30x40 room?

About 79 sheets of 4x8 drywall for the walls and ceiling with 8 ft walls, one door and one window, including 10% waste.

Room sizes

How Many Square Feet Is a 30x40 Room?

A 30x40 room is 1200 square feet (111.5 m²). Flooring with waste, paint, drywall and baseboard for a 30x40 room.

Updated October 12, 2026 · FloorFigures

Short answer

A 30x40 room is 1,200 square feet (30 × 40), or 111.5 m² and 133.3 square yards. Its perimeter is 140 ft. Flooring with 10% waste comes to about 1,320 sq ft.

Drawn to scale. Each grid square is 1 ft × 1 ft.

Materials for a 30x40 room

Estimates for a plain rectangular room with 8 ft ceilings, one door and one window. Adjust for your own room with the flooring, paint and drywall calculators.

Item	Quantity	Assumes
Floor area	1,200 sq ft	Wall to wall
Flooring to buy	1,320 sq ft (66 boxes)	10% waste, 20 sq ft boxes
Carpet	162 sq yd	12 ft roll, 2 seams
Wall area	1,084 sq ft	8 ft walls, less a door and a window
Paint, walls	6.2 gal (buy 7)	2 coats, 350 sq ft per gallon
Paint, walls and ceiling	13.1 gal	2 coats
Drywall	79 sheets	4x8 sheets, walls and ceiling, 10% waste
Baseboard	137 ft	Perimeter less a 3 ft door

What a 30x40 room is used for

Rooms this size are usually garages (a two-car garage is commonly 20–24 ft on each side), great rooms, basements or open-plan living areas. A queen bed (60" × 80") takes up about 33 sq ft, or 3% of the floor.

30x40 in other units

Unit	Value
Square feet	1,200
Square meters	111.48
Square yards	133.33
Square inches	172,800
Acres	0.0275
Dimensions in meters	9.14 × 12.19 m

Rooms close to 30x40

Room	Square feet	Square meters
20x22	440	40.9
20x24	480	44.6
22x22	484	45
22x24	528	49.1
24x24	576	53.5
20x30	600	55.7
24x30	720	66.9
24x36	864	80.3

Room not a simple rectangle? Use the square footage calculator for L-shapes and angled walls, or split it into rectangles.

Questions

How many square feet is a 30x40 room?: A 30 by 40 foot room is 1,200 square feet: 30 × 40 = 1,200. That's 111.5 square meters or 133.3 square yards.
How much flooring do I need for a 30x40 room?: Buy about 1,320 sq ft: the 1,200 sq ft floor plus 10% for cuts and waste. With boxes that cover 20 sq ft, that's 66 boxes. Diagonal or herringbone layouts need 15–20% extra instead.
How much paint do I need for a 30x40 room?: With 8 ft ceilings, one door and one window, the walls are about 1,084 sq ft. Two coats at 350 sq ft per gallon is 6.2 gallons, so buy 7. Painting the ceiling as well brings it to 13.1 gallons.
How many square meters is 30 by 40 feet?: 111.48 m². The room is 9.14 m by 12.19 m.
How many sheets of drywall for a 30x40 room?: About 79 sheets of 4x8 drywall for the walls and ceiling with 8 ft walls, one door and one window, including 10% waste.