Square Footage Calculator
How to Calculate Square Footage
Square footage is calculated by multiplying the length by the width of a space. For a 20-foot by 15-foot room, the area is 300 square feet. This measurement is essential for flooring, painting, landscaping, construction, and real estate. Different shapes use different formulas: rectangles use length times width, circles use pi times radius squared, and triangles use half of base times height. — also see our square root calculator. — also see our exponent calculator. Use the concrete calculator for related calculations. Related: use the Area Calculator to go further, or the Paint Calculator for a different angle.
Square Footage for Flooring
When ordering flooring materials, add 10 percent extra to your calculated square footage to account for waste from cutting, pattern matching, and potential mistakes. For diagonal or complex patterns, add 15 percent. Flooring is typically sold by the square foot or by the box, with each box covering a specified number of square feet.
Converting Between Area Units
One square yard equals 9 square feet. One square meter equals approximately 10.764 square feet. One acre equals 43,560 square feet. These conversions are built into this calculator for your convenience. For metric measurements, multiply square feet by 0.0929 to get square meters.
Tips for Measuring Rooms
For irregularly shaped rooms, divide the space into rectangles, calculate the area of each, and add them together. Measure from wall to wall and round up to the nearest inch. For rooms with closets, alcoves, or bump-outs, measure and add each section separately. Always measure twice before ordering materials.
What should you know before using this tool?
The Square Footage Calculator is built for people who want a fast answer without losing context. It keeps the calculation simple, shows the result clearly, and helps you understand what the number means before you use it in a real decision.
This calculator is designed to make a specific everyday calculation faster and clearer. It gives a structured result so you can compare options, check assumptions, or plan the next step with less manual work.
Why area calculation matters in everyday life
Calculating the area of a space — in square feet or square metres — is needed for flooring purchases, paint estimation, carpet buying, land valuation, rental agreements, construction planning, and agricultural measurement. Errors in area calculation lead directly to material waste or shortage. Understanding how to calculate area for different shapes helps you buy exactly what you need and interpret property listings correctly.
Area formulas for common shapes
Rectangle / Square: Area = Length × Width
A room 5.5 m × 4.2 m: Area = 5.5 × 4.2 = 23.1 m² = 248.7 sq ft
Triangle: Area = (Base × Height) ÷ 2
Triangular plot, base 12 m, height 8 m: Area = (12 × 8) ÷ 2 = 48 m²
Circle: Area = π × radius²
Circular garden, radius 4 m: Area = 3.14159 × 16 = 50.27 m²
L-shaped room: Break into two rectangles, calculate each, then add.
L-shape: 8m × 5m main + 4m × 3m extension = 40 + 12 = 52 m²
Trapezoid: Area = [(Base1 + Base2) ÷ 2] × Height
Converting between area units
- 1 m² = 10.764 sq ft
- 1 sq ft = 0.0929 m²
- 1 acre = 4,047 m² = 43,560 sq ft
- 1 hectare = 10,000 m² = 2.471 acres = 107,639 sq ft
- 1 square yard = 9 sq ft = 0.836 m²
- 1 square kilometre = 100 hectares = 247.1 acres = 1,000,000 m²
global land measurement units
India uses several traditional land area units alongside metric:
- Bigha: Highly variable by state. UP bigha ≈ 2,500 m². Punjab bigha ≈ 2,528 m². West Bengal bigha ≈ 1,337 m². Always confirm the local bigha standard.
- Marla: 25.29 m² = 272 sq ft (Punjab and Haryana). Used for urban residential plots.
- Kanal: 505.857 m² = 8 marla (Punjab and Haryana).
- Guntha: 101.17 m² (Maharashtra, Andhra Pradesh)
- Cent: 40.47 m² (South India, especially Tamil Nadu and Kerala) — 100 cents = 1 acre
- Ground: 222.97 m² = 2,400 sq ft (Tamil Nadu, primarily Chennai)
Practical area calculation for construction
Flooring: Calculate the room area in sq ft or m², add 10–15% for cuts and waste (more for diagonal or patterned installation). A 20 m² room needs approximately 22–23 m² of tiles or flooring material.
Paint: Calculate total wall area (perimeter × height) minus doors and windows. One litre of standard emulsion covers approximately 11–13 m² per coat.
Carpet/Rugs: Measure the exact area to be covered. Standard carpet widths are 3.66 m or 4 m — rooms wider than this require seaming.
Land valuation: Property prices are quoted per sq ft (urban), per sq yard (some cities), or per acre/bigha (agricultural). Always confirm the unit when comparing prices.
Carpet area vs built-up area vs super built-up area in India
Carpet area is the actual usable floor space — the area you can literally put carpet on. Built-up area includes carpet area plus walls and balcony (typically 10–15% more than carpet area). Super built-up area (SBA) — used by developers — includes carpet area plus a proportionate share of common areas (lobby, stairs, lifts, corridors), adding 25–30% over carpet area. RERA now mandates that apartment prices must be quoted on carpet area, making it the standard. A 1,200 sq ft "super built-up" flat may have only 850–900 sq ft of actual carpet area.
BHK apartment size expectations in India
| Type | Carpet Area (Typical) | Super Built-Up (Typical) |
|---|---|---|
| Studio / 1 RK | 250–350 sq ft | 350–450 sq ft |
| 1 BHK | 400–600 sq ft | 550–750 sq ft |
| 2 BHK | 650–950 sq ft | 850–1,200 sq ft |
| 3 BHK | 950–1,400 sq ft | 1,200–1,800 sq ft |
| 4 BHK / Villa | 1,500–2,500 sq ft | 2,000–3,200 sq ft |
Frequently asked questions
How do I calculate the area of an irregular plot? Divide the plot into triangles and rectangles, calculate each area separately, then sum. For GPS-based irregular land surveys, the coordinate method (Shoelace formula) calculates area from a series of coordinate points — professional surveyors use this with GPS equipment.
What is carpet area vs built-up area vs super built-up area? In global real estate: Carpet area = usable floor area inside walls. Built-up area = carpet area + wall thickness + balconies. Super built-up area = built-up area + share of common areas (corridors, lobby, lift). RERA now mandates pricing on carpet area to improve transparency.
How many square feet is a standard global urban plot? Common residential plot sizes: 30×40 ft (1,200 sq ft), 40×60 ft (2,400 sq ft), 50×80 ft (4,000 sq ft). In smaller cities, 20×30 ft (600 sq ft) or 25×40 ft (1,000 sq ft) are common. Premium locations use smaller high-value plots. — see also: area calculator
What is the average square footage of a bedroom or living room?
| Room Type | Small | Average | Large |
|---|---|---|---|
| Bedroom (US) | 100–130 sq ft | 150–200 sq ft | 250–400 sq ft |
| Living room (US) | 150–200 sq ft | 250–400 sq ft | 500+ sq ft |
| Kitchen (US) | 80–120 sq ft | 150–200 sq ft | 250–350 sq ft |
| Master bathroom | 50–70 sq ft | 80–120 sq ft | 150–250 sq ft |
| 1 BHK flat (India) | 400 sq ft | 550 sq ft | 650 sq ft |
| 2 BHK flat (India) | 700 sq ft | 900 sq ft | 1,100 sq ft |
Flooring cost estimates by material (installed)
| Material | Cost per sq ft (US) | Cost per sq ft (India) |
|---|---|---|
| Laminate | $3–8 | ₹60–150 |
| Hardwood | $8–20 | ₹150–400 |
| Ceramic tile | $5–15 | ₹80–300 |
| Vitrified tile (polished) | $6–12 | ₹100–250 |
| Carpet | $3–10 | ₹60–200 |
| Marble | $15–40 | ₹300–800 |
Sources & References
Sources: National Association of Realtors (NAR) — Standard Methods for Measuring Floor Area; ANSI Z765-2021 Square Footage Method for Calculating.
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