Area Converter (m², ft², yd²)

Understanding the area converter — concept and principle

Area tells you how much flat surface something covers: a flat, an office, a plot of land, a floor you want to tile. Listings in the United States quote square feet, most of the world uses square metres, land in some countries is measured in square kilometres or square miles, and Korean housing ads still often mention pyeong (평). This converter turns a value from one area unit into another and lists it in all the supported units at once.

How it is calculated

The value is converted to square metres, then divided by the size of the target unit: result = value × (m² per "from" unit) ÷ (m² per "to" unit). Key factors:

• 1 ft² = 0.09290304 m² (exact); 1 m² ≈ 10.7639 ft²
• 1 yd² = 9 ft² = 0.83612736 m²
• 1 in² = 6.4516 cm² = 0.00064516 m²
• 1 km² = 1,000,000 m²; 1 mi² ≈ 2,589,988.11 m² ≈ 2.59 km²
• 1 pyeong = 400/121 m² ≈ 3.305785 m²

The principle

An area unit is a square whose side is a length unit, so its size is the length factor squared. Since 1959 the international foot is exactly 0.3048 m, so 1 ft² = 0.3048² = 0.09290304 m², with no rounding at all. The same rule explains why 1 m² is 10,000 cm² and not 100: each side gets 100 times longer, so the area grows 100 × 100 times. A pyeong is a square of 6 × 6 ja; with 1 ja = 10/33 m, the side is 60/33 m and the area is (60/33)² = 400/121 m².

Worked example

Default input: 1,000 ft² to m².

1. Multiply by the exact factor: 1,000 × 0.09290304 = 92.90304 m².
2. In square yards: 1,000 ÷ 9 = 111.1111111 yd².
3. In square inches: 1,000 × 144 = 144,000 in².
4. In pyeong: 92.90304 ÷ 3.305785 ≈ 28.1031696 pyeong.

How to read the result

For a quick estimate, 1 m² is a little under 11 ft², so divide square feet by about 10.76 to get m², and divide m² by about 3.3 to get pyeong. A 1,000 ft² apartment is roughly 93 m², or 28 pyeong. When you compare listings, check whether the figure is the exclusive (net) floor area or a figure that includes shared spaces such as hallways and stairs; the difference can be large.

Common mistakes

• Using the length factor instead of its square, for example multiplying ft² by 0.3048.
• Thinking 1 m² = 100 cm²; it is 10,000 cm².
• Comparing a net floor area with a gross or supply area.
• Using the US survey foot for land records where it still applies; the difference is only about 2 parts per million.

Frequently asked questions

How many square feet are in a square metre?

About 10.7639 ft².

How many m² is one pyeong?

400/121 m², about 3.3058 m². One m² is about 0.3025 pyeong.

How many square metres is an acre?

An international acre is about 4,046.86 m², or 43,560 ft².

Why does 1 km² equal 1,000,000 m²?

A kilometre is 1,000 m, and area squares the factor: 1,000 × 1,000 = 1,000,000.

Sources: NIST Special Publication 811 (2008), Guide for the Use of the International System of Units, Appendix B · BIPM, The International System of Units (SI Brochure), 9th edition, 2019