30x40 in square feet, square yards and square meters
A pole barn, a three-bay shop or a small house is about this size. The area is length times width: 30 × 40 = 1,200 sq ft. Measure to the walls at the longest point, and add closets and alcoves you will floor.
| Unit | This room |
|---|---|
| Square feet | 1,200 sq ft |
| Square yards | 133.33 sq yd |
| Square meters | 111.48 sq m |
| Perimeter (around the walls) | 140 ft |
| Acres | 0.02755 acres |
What to buy for 1,200 sq ft
| Material | Amount |
|---|---|
| Flooring (10% waste, 20 sq ft boxes) | 1,320 sq ft, 66 boxes |
| Carpet off a 12 ft roll (before trimming) | 160.0 sq yd, 3 pieces |
| 12 × 12 in tiles (10% waste) | 1,320 tiles |
| Baseboard (full perimeter, before doorways) | 140 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 | 1,260 sq ft | 63 |
| 10% waste | 1,320 sq ft | 66 |
| 15% waste | 1,380 sq ft | 69 |
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.
30 × 40: a 1,200 square foot shop or small house
Thirty by forty is 1,200 sq ft, the footprint of a pole barn, a three-bay shop or a small single-story house. It measures 140 ft around and 50.0 ft from corner to corner (a 3-4-5 triangle scaled up, so the diagonal is exactly 50 ft, handy for squaring the layout). On a site plan it takes up 2.75% of an acre.
Nothing at this scale is bought by the box. A 4 in slab is about 16.3 cubic yards with a small overage, which means two ready-mix trucks, and shop floors that carry vehicles are often 5 or 6 in. As a house floor, 1,200 sq ft of plank is 66 boxes, but you would measure room by room and leave out the areas under cabinets and tubs. The outside walls alone, at 8 ft, are 1,120 sq ft; interior partitions add much more, so use the paint calculator per room.
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 a 30x40 room?
1,200 square feet (30 ft × 40 ft). That is 133.33 square yards or 111.48 square meters.
How many square feet of flooring do I need for a 30x40 room?
The floor is 1,200 sq ft, so buy about 1,320 sq ft with 10% for cuts and waste. That is 66 boxes at 20 sq ft a box.
How much carpet is a 30x40 room?
133.33 square yards of floor. Carpet comes off a 12 ft wide roll, so you buy whole strips: here 3 pieces 12 ft wide and 40 ft long, with 2 seams, which is 1,440 sq ft (160.0 sq yd) of carpet for a 1,200 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.