Square Kilometers to Square Nanometers: the quick answer
1 km² = 1 × 10²⁴ nm²
1 square kilometer equals 1 × 10²⁴ square nanometers
To convert square kilometers to square nanometers, multiply the value by 1 × 10²⁴. To go the other way, multiply square nanometers by 1 × 10⁻²⁴ to get square kilometers.