A barn is a nuclear cross-section unit equal to 1e-28 square meters.
Barns to Square Gigameters Converter — b to Gm2
Convert Barn (b) to Square Gigameter (Gm2) using the exact conversion factor (1 barn = 1e-46 square gigameter). See the formula, worked examples, and conversion table.
Barns to Square Gigameters 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.
Square metric area unit.
Result = input x 1e-28 / 1e+18.
Area uses the square meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Barns to Square Gigameters
Comparing Barn and Square Gigameter 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. Specifically: A barn is a nuclear cross-section unit equal to 1e-28 square meters, and square metric area unit.
Formula
square gigameters = barns × 1e-46
This factor comes from each unit's defined relationship to the category's base unit: 1 barn equals 1e-28 base units, and 1 square gigameter equals 1e+18 base units, so dividing one by the other gives the direct barn-to-square gigameter factor of 1e-46.
Simple example
1 b × 1e-46 = 1e-46 Gm2
1 barn = 1e-46 square gigameters.
Real-world example
10 b × 1e-46 = 1e-45 Gm2
10 barns = 1e-45 square gigameters.
Conversion table
| Barn (b) | Square Gigameter (Gm2) |
|---|---|
| 1 b | 1e-46 Gm2 |
| 5 b | 5e-46 Gm2 |
| 10 b | 1e-45 Gm2 |
| 25 b | 2.5e-45 Gm2 |
| 50 b | 5e-45 Gm2 |
| 100 b | 1e-44 Gm2 |
Reverse conversion: Square Gigameter to Barn
1e-46 Gm2 × 1e+46 = 1 b
1e-46 square gigameters = 1 barn.
barns = square gigameters × 1e+46
For a page dedicated to this direction, see Square Gigameter to Barn.
Understanding the Barn (b)
A barn is a nuclear cross-section unit equal to 1e-28 square meters.
Understanding the Square Gigameter (Gm2)
Square metric area unit.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many square gigameters are in 1 barn?
1 barn equals 1e-46 square gigameters, using the exact defined conversion factor rather than an estimate.
How do I convert barn to square gigameter?
Multiply the barn value by 1e-46. The converter above does this instantly to whatever precision you set.
How do I convert square gigameter back to barn?
Use the reverse factor: 1 square gigameter equals 1e+46 barns. You can also use the swap control in the converter above to flip the direction instantly.
What is a barn?
Barn (b) is a unit of area.
What is a square gigameter?
Square Gigameter (Gm2) is a unit of area.
Is the barn to square gigameter conversion exact?
Yes. Both barn and square gigameter are defined by fixed standards rather than physical artifacts, so the factor of 1e-46 used above is exact to as many digits as you choose to display.