Square feet is one of the most common units used to measure area, especially for homes, offices, and land. This page explains what a square foot is, how to calculate square footage from length and width, and how to convert it into other units such as square meters, square yards, acres, and marla. Use the calculator on this page for an instant result, or read on to understand the formula and conversion factors behind each unit.
Square Foot Definition and Uses
A square foot is the area of a square with each side measuring one foot. It belongs to the imperial and US customary system of measurement. Square footage is used across real estate, construction, interior design, and architecture. Countries such as the United States, Canada, the United Kingdom, and Pakistan all rely on square feet to describe the size of homes, offices, and land.
Square Foot Definition
One square foot equals 144 square inches. It is the area covered by a square whose sides are each one foot long. The unit is written as ft², and is also abbreviated as sq ft, sf, or sqft.
Common Uses of Square Footage
Square footage appears in many everyday situations. Home buyers and renters use it to compare property sizes. Flooring and tile projects use it to calculate the material needed. Painters use it to estimate paint coverage. Land and plot listings use it to state the size of a property. Architects use it when planning building layouts.
Square Footage Formula
Before converting square feet into any other unit, you first need to calculate the square footage itself. This means measuring the length and width of a space in feet, then multiplying the two numbers together. Both measurements must already be in the same unit before you calculate the area.
Basic Square Footage Formula
Area (sq ft) = Length (ft) × Width (ft)
For example, a room measuring 12 feet by 10 feet has an area of 120 square feet (12 × 10 = 120).
Square Footage for an Irregular Shaped Room
For an irregular room, split the space into smaller rectangles, calculate the area of each section, then add the totals together.
For example, an L shaped living room has a larger section (A) measuring 14 feet by 10 feet, and a smaller section (B) measuring 6 feet by 5 feet.
Section | Length × Width | Area (sq ft) |
A | 14 ft × 10 ft | 140 |
B | 6 ft × 5 ft | 30 |
Total | A + B | 170 |
Square Footage for a Wall
Wall area is calculated as height multiplied by length. For an accurate paint estimate, subtract the area of any doors and windows from the total.
For example, a wall that is 8 feet high and 15 feet long has a total area of 120 sq ft (8 × 15 = 120). If a door takes up 20 sq ft, the paintable area is 100 sq ft (120 - 20 = 100).
Square Feet Conversion Factors
Once you know the area in square feet, you can convert it into other units of area. Each unit has a fixed conversion factor. Multiplying or dividing the square feet value by this factor gives the equivalent area in square meters, square yards, acres, or any other unit. Every conversion on this page starts from the same square feet value.
General Conversion Formula
Value in square feet × Conversion factor = Value in target unit
Each unit below has its own conversion factor, covered individually further down this page.
Square Feet Conversion Factors Table
Convert Square Feet To | Multiply By |
Square Meters | 0.092903 |
Square Yards | 0.111111 |
Square Inches | 144 |
Acres | 0.0000229568 |
Hectares | 0.0000092903 |
Square Meters to Square Feet (reverse) | 10.7639 |
Common Square Feet Conversion Mistakes
A few mistakes are common when working with square feet. Mixing units before calculating the area is one. Rounding the conversion factor too early is another. Both can lead to results that are noticeably wrong, especially on larger properties.
Mixing Units Before Calculating
Measuring one side of a room in feet and another side in inches, without converting first, produces an incorrect area.
Method | Calculation | Result |
Wrong | 10 ft × 36 (inches, not converted) | 360, an incorrect and meaningless number |
Correct | 10 ft × 3 ft (36 inches converted to feet first) | 30 sq ft |
Rounding Errors on Large Areas
Rounding 0.092903 down to 0.09 looks harmless for a small room, but the gap grows on larger areas. For a 10,000 sq ft commercial plot, the accurate conversion gives 929.03 sq m, while the rounded factor gives 900 sq m, a difference of 29.03 sq m.
Popular Square Feet Conversions
Square feet gets converted into different units depending on the situation. Real estate deals often need square meters or, in Pakistan and India, marla and kanal. Construction projects often need square yards or acres, while small object measurements often need square inches. The conversions below cover each of these in detail.
Square Feet to Square Meters
Square feet × 0.092903 = square meters. For example, 500 sq ft equals 46.45 sq m (500 × 0.092903 = 46.4515). Use the dedicated square feet to square meters calculator for the full working and more examples.
Square Meters to Square Feet
Square meters × 10.7639 = square feet. For example, 50 sq m equals 538.2 sq ft (50 × 10.7639 = 538.195). Use the dedicated square meters to square feet calculator for the full tool.
Square Feet to Square Yards
Square feet ÷ 9 = square yards. For example, 900 sq ft equals 100 sq yd (900 ÷ 9 = 100). This conversion is common when pricing carpet and flooring material sold by the yard. Use the dedicated square feet to square yards calculator.
Square Feet to Acres
Square feet ÷ 43,560 = acres. For example, a 100,000 sq ft plot equals about 2.30 acres (100,000 ÷ 43,560 = 2.296). Use the dedicated square feet to acres calculator.
Square Feet to Square Inches
Square feet × 144 = square inches. For example, a 2 sq ft tile equals 288 sq in (2 × 144 = 288). Use the dedicated square feet to square inches calculator.
Square Feet to Hectares
Square feet × 0.0000092903 = hectares. For example, a 500,000 sq ft farm plot equals about 4.65 hectares (500,000 × 0.0000092903 = 4.645). Use the dedicated square feet to hectares calculator.
Square Feet to Marla and Kanal
Marla and kanal are traditional land units used mainly in Pakistan and parts of India for residential plots. Under the standard used by most modern housing societies, 1 marla equals 225 sq ft, and 1 kanal equals 20 marla, or 4,500 sq ft. Some rural revenue records use an older standard of 272.25 sq ft per marla, so confirm which standard applies to your property before relying on the number.
For example, a 1,000 sq ft plot equals about 4.44 marla under the 225 sq ft standard (1,000 ÷ 225 = 4.44).
Standard | 1 Marla (sq ft) | 1 Kanal (sq ft) |
Urban housing societies | 225 | 4,500 |
Rural revenue records | 272.25 | 5,445 |
Use the dedicated square feet to marla and kanal calculator for the full working.
Cost Per Square Foot Calculator
Total price ÷ total square footage = price per square foot. For example, a home priced at 15,000,000 with an area of 2,250 sq ft costs about 6,667 per sq ft (15,000,000 ÷ 2,250 = 6,666.67). This figure helps compare properties of different sizes. Use the dedicated cost per square foot calculator.
Square Footage for Flooring and Tile
Measure the room in square feet using the formula covered earlier, then add about 10 percent extra to the total for waste and cuts. For example, a room measuring 170 sq ft needs about 187 sq ft of material once waste is included (170 × 1.10 = 187). Use the dedicated flooring square footage calculator.
Square Footage for Painting
Measure each wall as height × length, subtract the area of doors and windows, then add all walls together for the room total. One gallon of paint typically covers 200 to 400 sq ft, so the total square footage tells you how many gallons to buy. Use the dedicated paint square footage calculator.