Square metric area unit.
Square Kilometers to Barns Converter — km2 to b
Convert Square Kilometer (km2) to Barn (b) using the exact conversion factor (1 square kilometer = 1e+34 barn). See the formula, worked examples, conversion table, history, and common uses.
Square Kilometers to Barns converter
Converter
Area Converter
Convert land, construction, mapping, survey, and scientific area units.
Context values
Some unit families need one extra value for a physically accurate result.
A barn is a nuclear cross-section unit equal to 1e-28 square meters.
Result = input x 1e+6 / 1e-28.
Area uses the square meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Square Kilometers to Barns
Comparing Square Kilometer and Barn is common in agriculture and real estate, where US land is typically measured in acres and most of the rest of the world uses hectares. Square Kilometer is most often used for national and regional land-area statistics.
Formula
barns = square kilometers × 1e+34
This factor comes from each unit's defined relationship to the category's base unit: 1 square kilometer equals 1000000 base units, and 1 barn equals 1e-28 base units, so dividing one by the other gives the direct square kilometer-to-barn factor of 1e+34.
Simple example
1 km2 × 1e+34 = 1e+34 b
1 square kilometer = 1e+34 barns.
Real-world example
10 km2 × 1e+34 = 1e+35 b
10 square kilometers = 1e+35 barns.
Conversion table
| Square Kilometer (km2) | Barn (b) |
|---|---|
| 1 km2 | 1e+34 b |
| 5 km2 | 5e+34 b |
| 10 km2 | 1e+35 b |
| 25 km2 | 2.5e+35 b |
| 50 km2 | 5e+35 b |
| 100 km2 | 1e+36 b |
Reverse conversion: Barn to Square Kilometer
1e+34 b × 1e-34 = 1 km2
1e+34 barns = 1 square kilometers.
square kilometers = barns × 1e-34
For a page dedicated to this direction, see Barn to Square Kilometer.
Understanding the Square Kilometer
Square Kilometer (km2) measures area. A square kilometer is one million square meters — the area of a 1 km × 1 km square. It is classified as a SI derived (metric prefix) unit.
Where it's used: Used worldwide for city, region, and country-scale area reporting.
Uses of the Square Kilometer today
- National and regional land-area statistics
- City and urban planning at large scale
- Geography and cartography
History of the Square Kilometer
Like other metric-prefixed area units, the square kilometer follows automatically from the kilometer once the meter was standardized in the 1790s French metric reform.
Historical origin. Square Kilometer was not the invention of a single named person; it developed through the process described above.
Understanding the Barn (b)
A barn is a nuclear cross-section unit equal to 1e-28 square meters.
Square Kilometer — sources
- BIPM SI Brochure — Coherent derived units — Basis for metric-prefixed area units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many barns are in 1 square kilometer?
1 square kilometer equals 1e+34 barns, using the exact defined conversion factor rather than an estimate.
How do I convert square kilometer to barn?
Multiply the square kilometer value by 1e+34. The converter above does this instantly to whatever precision you set.
How do I convert barn back to square kilometer?
Use the reverse factor: 1 barn equals 1e-34 square kilometers. You can also use the swap control in the converter above to flip the direction instantly.
What is a square kilometer?
Square Kilometer (km2) measures area. A square kilometer is one million square meters — the area of a 1 km × 1 km square. It is classified as a SI derived (metric prefix) unit.
What is a barn?
Barn (b) is a unit of area.
Is the square kilometer to barn conversion exact?
Yes. Both square kilometer and barn are defined by fixed standards rather than physical artifacts, so the factor of 1e+34 used above is exact to as many digits as you choose to display.
Where is the square kilometer still used today?
Used worldwide for city, region, and country-scale area reporting.