How Many Square Feet Is a 15x20 Room?
A 15 ft × 20 ft room equals 300 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 15x20 Room
| Metric | Value |
|---|---|
| Floor area | 300 sq ft |
| Floor area (m²) | 27.87 m² |
| Floor area (sq yd) | 33.33 sq yd |
| Perimeter | 70 ft |
| Wall area (8 ft ceiling) | 560 sq ft |
| Wall area (9 ft ceiling) | 630 sq ft |
| Wall area (10 ft ceiling) | 700 sq ft |
Common Uses for a 15x20 Space
- great room
- large living
At 300 sq ft, this falls in the large category — sized for great rooms, master suites, or single-car garages.
Best Furniture Layout for a 15x20 Room
At 300 sq ft, a 15x20 space supports distinct zones — for example sleeping + seating in a primary suite, or dining + buffet in a family room. The long, narrow layout lets you divide the room visually with a rug or lighting without building walls.
- King bed + sitting area (2 chairs + side table) + walk-in closet zone on one end.
- 10 ft sectional + 48 in coffee table + media wall + console behind sofa.
- Single-car garage layout: one full-size vehicle + 3 ft side storage aisle.
15x20 vs Other Common Room Sizes
If you are deciding between two footprints, compare total square footage and how each layout affects furniture clearance — not just the length and width numbers.
- 16×18 — saves 12 sq ft versus 16×18 — tighter furniture layout.
- 16×20 — adds 20 sq ft over 16×20 — more seating or storage options.
How Much Flooring Will You Need?
Wondering how much flooring do I need for a 15x20 room? The floor area is 300 sq ft — buy that much plus a waste allowance:
| Flooring Type | Waste % | Buy This Much |
|---|---|---|
| Laminate / LVP (plank) | 10% | 330 sq ft |
| Hardwood | 10% | 330 sq ft |
| Ceramic tile (straight) | 10% | 330 sq ft |
| Ceramic tile (diagonal) | 15% | 345 sq ft |
| Carpet | 10% | 330 sq ft (37 sq yd) |
Need an exact estimate? Use our Flooring Calculator for plank count, or the Tile Calculator for boxes of tile.
How Many Gallons of Paint for a 15x20 Room?
With 8 ft ceilings you'll paint about 560 sq ft of wall. A gallon covers ~350 sq ft, so you'll need 2 gallons per coat and 4 gallons for two coats.
Detailed breakdown on our Paint Calculator.
Is a 15x20 Room Big?
This is a large room — great for primary suites, family rooms, or open-plan spaces.
How Much Does It Cost to Build a 15x20 Room?
At typical US rates of $150–$300 per sq ft for new construction, a 15x20 addition would cost roughly $45,000–$90,000. For remodels:
- Basic flooring replacement: $900–$3,000
- Mid-range remodel: $15,000–$30,000
- Full gut renovation: $30,000–$75,000
Refine with our Cost per Square Foot Calculator.
Frequently Asked Questions
How many square feet is 15x20?
15 × 20 = 300 square feet.
How many square meters is 15x20?
27.87 m².
How many tiles will fit in a 15x20 room?
Depends on tile size. 12"×12" tiles = 330 tiles (with 10% waste). See our Tile Calculator for 6", 18", and 24" sizes.
How much carpet do I need for a 15x20 room?
33.33 sq yd minimum, or 36.67 sq yd with 10% waste for cuts and seams.
How many gallons of paint for a 15x20 room?
About 560 sq ft of wall at 8 ft ceilings. One coat needs 2 gallons; two coats need 4 gallons at 350 sq ft per gallon.
How much flooring do I need for a 15x20 room?
300 sq ft of floor area. With a 10% waste factor, order 330 sq ft of laminate, hardwood, or LVP. See the Flooring Calculator for box counts.
What furniture fits in a 15x20 room?
King bed + sitting area (2 chairs + side table) + walk-in closet zone on one end.