How Many Square Feet Is a 18x24 Room?
A 18 ft × 24 ft room equals 432 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 18x24 Room
| Metric | Value |
|---|---|
| Floor area | 432 sq ft |
| Floor area (m²) | 40.13 m² |
| Floor area (sq yd) | 48.00 sq yd |
| Perimeter | 84 ft |
| Wall area (8 ft ceiling) | 672 sq ft |
| Wall area (9 ft ceiling) | 756 sq ft |
| Wall area (10 ft ceiling) | 840 sq ft |
Common Uses for a 18x24 Space
- great room
- 2-car garage
At 432 sq ft, this falls in the xlarge category — best suited for two-car garages, workshops, or open great rooms.
How Much Flooring Will You Need?
For a 18' × 24' room, buy enough flooring to cover 432 sq ft plus a waste allowance:
| Flooring Type | Waste % | Buy This Much |
|---|---|---|
| Laminate / LVP (plank) | 10% | 476 sq ft |
| Hardwood | 10% | 476 sq ft |
| Ceramic tile (straight) | 10% | 476 sq ft |
| Ceramic tile (diagonal) | 15% | 497 sq ft |
| Carpet | 10% | 476 sq ft (53 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 18x24 Room?
With 8 ft ceilings you'll paint about 672 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 18x24 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 18x24 Room?
At typical US rates of $150–$300 per sq ft for new construction, a 18x24 addition would cost roughly $64,800–$129,600. For remodels:
- Basic flooring replacement: $1,296–$4,320
- Mid-range remodel: $21,600–$43,200
- Full gut renovation: $43,200–$108,000
Refine with our Cost per Square Foot Calculator.
Frequently Asked Questions
How many square feet is 18x24?
18 × 24 = 432 square feet.
How many square meters is 18x24?
40.13 m².
How many tiles will fit in a 18x24 room?
Depends on tile size. 12"×12" tiles = 476 tiles (with 10% waste). See our Tile Calculator for 6", 18", and 24" sizes.
How much carpet do I need for a 18x24 room?
48.00 sq yd minimum, or 52.80 sq yd with 10% waste for cuts and seams.