How Many Square Feet Is a 20x20 Room?
A 20 ft × 20 ft room equals 400 square feet. Use the calculator below to double-check or customize with waste and cost.
Last updated:Tip: If you only have the diameter, divide by 2 to get the radius.
L-shape = two rectangles sharing a corner.
Add one row per rectangle and we'll sum them.
Key Measurements for a 20x20 Room
| Metric | Value |
|---|---|
| Floor area | 400 sq ft |
| Floor area (m²) | 37.16 m² |
| Floor area (sq yd) | 44.44 sq yd |
| Perimeter | 80 ft |
| Wall area (8 ft ceiling) | 640 sq ft |
| Wall area (9 ft ceiling) | 720 sq ft |
| Wall area (10 ft ceiling) | 800 sq ft |
Common Uses for a 20x20 Space
- 2-car garage
- great room
At 400 sq ft, this falls in the large category — sized for great rooms, master suites, or single-car garages.
How Much Flooring Will You Need?
For a 20' × 20' room, buy enough flooring to cover 400 sq ft plus a waste allowance:
| Flooring Type | Waste % | Buy This Much |
|---|---|---|
| Laminate / LVP (plank) | 10% | 441 sq ft |
| Hardwood | 10% | 441 sq ft |
| Ceramic tile (straight) | 10% | 441 sq ft |
| Ceramic tile (diagonal) | 15% | 460 sq ft |
| Carpet | 10% | 441 sq ft (49 sq yd) |
Need an exact estimate? Use our Flooring Calculator for plank count, or the Tile Calculator for boxes of tile.
How Much Paint for a 20x20 Room?
With 8 ft ceilings you'll paint about 640 sq ft of wall. A gallon covers ~350 sq ft, so you'll need 2 gallons per coat. Plan on two coats for a color change.
Detailed breakdown on our Paint Calculator.
Is a 20x20 Room Big?
This is an extra-large space, ideal for great rooms, large primary suites, or a single-car garage with storage.
How Much Does It Cost to Build a 20x20 Room?
At typical US rates of $150–$300 per sq ft for new construction, a 20x20 addition would cost roughly $60,000–$120,000. For remodels:
- Basic flooring replacement: $1,200–$4,000
- Mid-range remodel: $20,000–$40,000
- Full gut renovation: $40,000–$100,000
Refine with our Cost per Square Foot Calculator.
Frequently Asked Questions
How many square feet is 20x20?
20 × 20 = 400 square feet.
How many square meters is 20x20?
37.16 m².
How many tiles will fit in a 20x20 room?
Depends on tile size. 12"×12" tiles = 441 tiles (with 10% waste). See our Tile Calculator for 6", 18", and 24" sizes.
How much carpet do I need for a 20x20 room?
44.44 sq yd minimum, or 48.89 sq yd with 10% waste for cuts and seams.