How much flooring do I need for a 18x20 room?

Buy about 396 sq ft: the 360 sq ft floor plus 10% for cuts and waste. With boxes that cover 20 sq ft, that's 20 boxes. Diagonal or herringbone layouts need 15–20% extra instead.

How much paint do I need for a 18x20 room?

With 8 ft ceilings, one door and one window, the walls are about 572 sq ft. Two coats at 350 sq ft per gallon is 3.3 gallons, so buy 4. Painting the ceiling as well brings it to 5.3 gallons.

How many square meters is 18 by 20 feet?

33.45 m². The room is 5.49 m by 6.1 m.

How many sheets of drywall for a 18x20 room?

About 33 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 18x20 Room?

A 18x20 room is 360 square feet (33.4 m²). Flooring with waste, paint, drywall and baseboard for a 18x20 room.

Updated October 12, 2026 · FloorFigures

Short answer

A 18x20 room is 360 square feet (18 × 20), or 33.4 m² and 40 square yards. Its perimeter is 76 ft. Flooring with 10% waste comes to about 396 sq ft.

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

Materials for a 18x20 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	360 sq ft	Wall to wall
Flooring to buy	396 sq ft (20 boxes)	10% waste, 20 sq ft boxes
Carpet	49.3 sq yd	12 ft roll, 1 seam
Wall area	572 sq ft	8 ft walls, less a door and a window
Paint, walls	3.3 gal (buy 4)	2 coats, 350 sq ft per gallon
Paint, walls and ceiling	5.3 gal	2 coats
Drywall	33 sheets	4x8 sheets, walls and ceiling, 10% waste
Baseboard	73 ft	Perimeter less a 3 ft door

What a 18x20 room is used for

Rooms this size are usually living rooms, family rooms, large primary suites or open kitchens. A queen bed (60" × 80") takes up about 33 sq ft, or 9% of the floor.

18x20 in other units

Unit	Value
Square feet	360
Square meters	33.45
Square yards	40
Square inches	51,840
Acres	0.0083
Dimensions in meters	5.49 × 6.1 m

Rooms close to 18x20

Room	Square feet	Square meters
12x24	288	26.8
16x18	288	26.8
15x20	300	27.9
16x20	320	29.7
18x18	324	30.1
16x24	384	35.7
20x20	400	37.2
18x24	432	40.1

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 18x20 room?: A 18 by 20 foot room is 360 square feet: 18 × 20 = 360. That's 33.4 square meters or 40 square yards.
How much flooring do I need for a 18x20 room?: Buy about 396 sq ft: the 360 sq ft floor plus 10% for cuts and waste. With boxes that cover 20 sq ft, that's 20 boxes. Diagonal or herringbone layouts need 15–20% extra instead.
How much paint do I need for a 18x20 room?: With 8 ft ceilings, one door and one window, the walls are about 572 sq ft. Two coats at 350 sq ft per gallon is 3.3 gallons, so buy 4. Painting the ceiling as well brings it to 5.3 gallons.
How many square meters is 18 by 20 feet?: 33.45 m². The room is 5.49 m by 6.1 m.
How many sheets of drywall for a 18x20 room?: About 33 sheets of 4x8 drywall for the walls and ceiling with 8 ft walls, one door and one window, including 10% waste.