Square Foot (US Survey) to Square Kilometer Converter
Unit Converter
Instant · Precise · Universal
23 units available
6 categories total
How to Convert Square Foot (US Survey) to Square Kilometer
To convert US survey ft² to m²: multiply by 0.09290341. To international ft²: multiply by ~1.000004.
1 ft² (US) ≈ 0.09290341 m². Differs from international ft² (0.09290304 m²) by about 4 × 10⁻⁷ m².
For example, 1 Square Foot (US Survey) (ft² (US)) = 9.290341e-8 Square Kilometer (km²).
Square Foot (US Survey) to Square Kilometer — Common Values
| Square Foot (US Survey) (ft² (US)) | Square Kilometer (km²) |
|---|---|
| 0.1 | 9.290341e-9 |
| 0.5 | 4.645171e-8 |
| 1 | 9.290341e-8 |
| 2 | 1.858068e-7 |
| 5 | 4.645171e-7 |
| 10 | 9.290341e-7 |
| 25 | 0.00000232258529 |
| 50 | 0.000004645170581 |
| 100 | 0.000009290341161 |
| 500 | 0.00004645170581 |
| 1000 | 0.00009290341161 |
About Square Foot (US Survey) (ft² (US))
Definition
The US survey square foot is a historical area unit based on the US survey foot (1200/3937 m), equal to approximately 0.09290341 m².
Mathematical Relationship
1 ft² (US) ≈ 0.09290341 m². Differs from international ft² (0.09290304 m²) by about 4 × 10⁻⁷ m².
Conversion Formula
To convert US survey ft² to m²: multiply by 0.09290341. To international ft²: multiply by ~1.000004.
Practical Applications
Historical property records and government land survey documents.
Interesting Facts
The difference from the international square foot is only about 0.4 mm² — negligible for a single measurement, but significant over millions of square feet.
Common Mistakes
Using the US survey foot in new work. Since 2023, only the international foot is valid in the US.
Educational Tips
The US survey foot existed because of a historical definition difference. It's now retired — use the international foot (exactly 0.3048 m).
About Square Kilometer (km²)
Definition
The square kilometer is a metric unit of area equal to 1,000,000 square meters, or a square with sides of 1 kilometer.
Mathematical Relationship
1 km² = 1,000,000 m² = 100 ha = 247.105 acres ≈ 0.3861 mi².
Conversion Formula
To convert km² to mi²: multiply by 0.3861. To hectares: multiply by 100. To acres: multiply by 247.105.
Practical Applications
Country areas, national park sizes, city footprints, forest coverage, and watershed boundaries.
Interesting Facts
Vatican City = 0.44 km². Manhattan = 59.1 km². Russia = 17,098,242 km² (largest country). Earth's surface = 510,072,000 km².
Common Mistakes
Thinking 1 km² = 1,000 m² (it's actually 1,000,000 m²). Area scales as the square of the linear dimension.
Educational Tips
1 km = 1,000 m, but 1 km² = 1,000² m² = 1,000,000 m². Always square the conversion factor for area.