Room Size Calculator
Find the total size of any room for flooring, paint, or remodeling.
Room Size Calculator
What This Calculator Does
The Room Size Calculator provides the complete dimensions of any room: floor area, wall area (for paint or wallpaper), and square yards. Enter the room length, width, and optionally ceiling height to get all three measurements at once - saving you from calculating each separately.
Planning a room renovation requires multiple measurements. Floor area determines flooring, tile, or carpet needs. Wall area tells you how much paint or wallpaper to buy. Ceiling height affects paint volume and helps with material takeoffs for crown molding or wainscoting. Getting all of these from one entry saves time and ensures consistency.
This calculator works for any rectangular room including bedrooms, living rooms, bathrooms, kitchens, and office spaces. For L-shaped or irregular rooms, divide into rectangles, calculate each section, and add the results.
How to Use
- Measure the length and width of the room in feet at the longest points. Use a laser measure for accuracy.
- If you need wall area for paint or wallpaper, measure the ceiling height in feet (standard US is 8 or 9 ft).
- Enter all dimensions into the calculator fields above.
- Click "Calculate" to see floor area, wall area, and square yards instantly.
- Use the results to order flooring, estimate paint, or request contractor quotes.
Worked Examples
Master Bedroom Flooring and Paint Takeoff
A 14 x 16 ft master bedroom with 9-ft ceilings, one door, and two windows needs both hardwood flooring and fresh paint.
- →Floor area: 14 ft x 16 ft = 224 sq ft. Order hardwood with 10% waste: 224 x 1.10 = 246.4 sq ft.
- →Wall perimeter: 2 x (14 + 16) = 60 ft. Gross wall area: 60 ft x 9 ft = 540 sq ft.
- →Subtract 1 door (21 sq ft) and 2 windows (30 sq ft): 540 - 51 = 489 sq ft net wall area.
- →At 400 sq ft per gallon: 489 / 400 = 1.22 gallons per coat. Round up to 2 gallons per coat, 4 gallons for two coats.
Result: 224 sq ft floor area needing ~247 sq ft of hardwood; 489 sq ft net wall area needing 4 gallons of paint for two coats.
For the most accurate planning estimate, measure each wall individually rather than using perimeter math — alcoves, bay windows, and built-ins change the actual wall area.
Reference Table
| Room Size | Floor Area | Wall Area (8 ft) | Wall Area (9 ft) |
|---|---|---|---|
| 10 x 10 ft | 100 sq ft | 320 sq ft | 360 sq ft |
| 12 x 12 ft | 144 sq ft | 384 sq ft | 432 sq ft |
| 12 x 16 ft | 192 sq ft | 448 sq ft | 504 sq ft |
| 14 x 18 ft | 252 sq ft | 512 sq ft | 576 sq ft |
| 20 x 20 ft | 400 sq ft | 640 sq ft | 720 sq ft |
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Frequently Asked Questions
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