18x20 in square feet, square yards and square meters
A tight two-car garage or a large living room is about this size. The area is length times width: 18 × 20 = 360 sq ft. Measure to the walls at the longest point, and add closets and alcoves you will floor.
| Unit | This room |
|---|---|
| Square feet | 360 sq ft |
| Square yards | 40.00 sq yd |
| Square meters | 33.45 sq m |
| Perimeter (around the walls) | 76 ft |
| Acres | 0.00826 acres |
What to buy for 360 sq ft
| Material | Amount |
|---|---|
| Flooring (10% waste, 20 sq ft boxes) | 396 sq ft, 20 boxes |
| Carpet off a 12 ft roll (before trimming) | 48.0 sq yd, 2 pieces |
| Wall paint (8 ft walls, 1 door, 2 windows, 2 coats) | 3 gallons + 1 quart |
| 12 × 12 in tiles (10% waste) | 396 tiles |
| Baseboard (full perimeter, before doorways) | 76 ft |
Flooring with different waste allowances
Straight layouts need about 5 to 7%, diagonal layouts 10%, and herringbone or patterns 15%.
| Waste | Flooring to buy | Boxes of 20 sq ft |
|---|---|---|
| 5% waste | 378 sq ft | 19 |
| 10% waste | 396 sq ft | 20 |
| 15% waste | 414 sq ft | 21 |
Use the square footage calculator for L-shaped rooms, circles and triangles, the carpet calculator for the roll layout with trimming, or the flooring calculator for a full flooring estimate.
360 square feet: an 18 × 20 space
Eighteen by twenty is 360 sq ft. That is a tight two-car garage, a large living room, or a classroom-sized studio. As a garage, two cars fit but the doors open close to each other and there is little storage depth. As a living room a 12 × 15 ft rug leaves 3.0 ft at the sides and 2.5 ft at the ends, and the room can carry two separate seating groups.
Because both sides are over 12 ft, any carpet will have a seam, and the fitter decides where it falls; the order is about 48.0 sq yd off a 12 ft roll. Plank flooring is 20 boxes, enough weight that delivery is worth paying for. Two coats on the walls take 3.18 gallons (3 gallons + 1 quart), and a 4 in garage slab this size is roughly 4.9 cubic yards.
Want to change anything else? The calculator above is the full Square Footage Calculator: edit any number and the results update instantly.
Frequently asked questions
How many square feet is an 18x20 room?
360 square feet (18 ft × 20 ft). That is 40.00 square yards or 33.45 square meters.
How many square feet of flooring do I need for an 18x20 room?
The floor is 360 sq ft, so buy about 396 sq ft with 10% for cuts and waste. That is 20 boxes at 20 sq ft a box.
How much carpet is an 18x20 room?
40.00 square yards of floor. Carpet comes off a 12 ft wide roll, so you buy whole strips: here 2 pieces 12 ft wide and 18 ft long, with a seam, which is 432 sq ft (48.0 sq yd) of carpet for a 360 sq ft floor, plus a few inches a strip for trimming.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.