Square Miles to Barns: the quick answer
1 mi² = 2.58999 × 10³⁴ b
1 square mile equals 2.58999 × 10³⁴ barns
To convert square miles to barns, multiply the value by 2.58999 × 10³⁴. To go the other way, multiply barns by 3.86102 × 10⁻³⁵ to get square miles.