| 0km² | 0b |
| 1km² | 1 × 10³⁴b |
| 2km² | 2 × 10³⁴b |
| 3km² | 3 × 10³⁴b |
| 4km² | 4 × 10³⁴b |
| 5km² | 5 × 10³⁴b |
| 6km² | 6 × 10³⁴b |
| 7km² | 7 × 10³⁴b |
| 8km² | 8 × 10³⁴b |
| 9km² | 9 × 10³⁴b |
| 10km² | 1 × 10³⁵b |
| 11km² | 1.1 × 10³⁵b |
| 12km² | 1.2 × 10³⁵b |
| 13km² | 1.3 × 10³⁵b |
| 14km² | 1.4 × 10³⁵b |
| 15km² | 1.5 × 10³⁵b |
| 16km² | 1.6 × 10³⁵b |
| 17km² | 1.7 × 10³⁵b |
| 18km² | 1.8 × 10³⁵b |
| 19km² | 1.9 × 10³⁵b |
| 20km² | 2 × 10³⁵b |
| 21km² | 2.1 × 10³⁵b |
| 22km² | 2.2 × 10³⁵b |
| 23km² | 2.3 × 10³⁵b |
| 24km² | 2.4 × 10³⁵b |
| 25km² | 2.5 × 10³⁵b |
| 26km² | 2.6 × 10³⁵b |
| 27km² | 2.7 × 10³⁵b |
| 28km² | 2.8 × 10³⁵b |
| 29km² | 2.9 × 10³⁵b |
| 30km² | 3 × 10³⁵b |
| 31km² | 3.1 × 10³⁵b |
| 32km² | 3.2 × 10³⁵b |
| 33km² | 3.3 × 10³⁵b |
| 34km² | 3.4 × 10³⁵b |
| 35km² | 3.5 × 10³⁵b |
| 36km² | 3.6 × 10³⁵b |
| 37km² | 3.7 × 10³⁵b |
| 38km² | 3.8 × 10³⁵b |
| 39km² | 3.9 × 10³⁵b |
| 40km² | 4 × 10³⁵b |
| 41km² | 4.1 × 10³⁵b |
| 42km² | 4.2 × 10³⁵b |
| 43km² | 4.3 × 10³⁵b |
| 44km² | 4.4 × 10³⁵b |
| 45km² | 4.5 × 10³⁵b |
| 46km² | 4.6 × 10³⁵b |
| 47km² | 4.7 × 10³⁵b |
| 48km² | 4.8 × 10³⁵b |
| 49km² | 4.9 × 10³⁵b |
| 50km² | 5 × 10³⁵b |
| 51km² | 5.1 × 10³⁵b |
| 52km² | 5.2 × 10³⁵b |
| 53km² | 5.3 × 10³⁵b |
| 54km² | 5.4 × 10³⁵b |
| 55km² | 5.5 × 10³⁵b |
| 56km² | 5.6 × 10³⁵b |
| 57km² | 5.7 × 10³⁵b |
| 58km² | 5.8 × 10³⁵b |
| 59km² | 5.9 × 10³⁵b |
| 60km² | 6 × 10³⁵b |
| 61km² | 6.1 × 10³⁵b |
| 62km² | 6.2 × 10³⁵b |
| 63km² | 6.3 × 10³⁵b |
| 64km² | 6.4 × 10³⁵b |
| 65km² | 6.5 × 10³⁵b |
| 66km² | 6.6 × 10³⁵b |
| 67km² | 6.7 × 10³⁵b |
| 68km² | 6.8 × 10³⁵b |
| 69km² | 6.9 × 10³⁵b |
| 70km² | 7 × 10³⁵b |
| 71km² | 7.1 × 10³⁵b |
| 72km² | 7.2 × 10³⁵b |
| 73km² | 7.3 × 10³⁵b |
| 74km² | 7.4 × 10³⁵b |
| 75km² | 7.5 × 10³⁵b |
| 76km² | 7.6 × 10³⁵b |
| 77km² | 7.7 × 10³⁵b |
| 78km² | 7.8 × 10³⁵b |
| 79km² | 7.9 × 10³⁵b |
| 80km² | 8 × 10³⁵b |
| 81km² | 8.1 × 10³⁵b |
| 82km² | 8.2 × 10³⁵b |
| 83km² | 8.3 × 10³⁵b |
| 84km² | 8.4 × 10³⁵b |
| 85km² | 8.5 × 10³⁵b |
| 86km² | 8.6 × 10³⁵b |
| 87km² | 8.7 × 10³⁵b |
| 88km² | 8.8 × 10³⁵b |
| 89km² | 8.9 × 10³⁵b |
| 90km² | 9 × 10³⁵b |
| 91km² | 9.1 × 10³⁵b |
| 92km² | 9.2 × 10³⁵b |
| 93km² | 9.3 × 10³⁵b |
| 94km² | 9.4 × 10³⁵b |
| 95km² | 9.5 × 10³⁵b |
| 96km² | 9.6 × 10³⁵b |
| 97km² | 9.7 × 10³⁵b |
| 98km² | 9.8 × 10³⁵b |
| 99km² | 9.9 × 10³⁵b |
The square kilometre is a unit of area and is a multiple of the square metre; an SI derived unit. It has the symbol km².
A square kilometre is equal to the area of a square with edges 1km long. There are 1,000,000 square metres in a square kilometre.
Square kilometres are often used to describe expansive areas of land due to the large unit size.
The barn is a unit of area and is used in particle physics with the symbol b.
It represents approximately the area of the cross-section of a uraneum nucleus, so is very small compared to most other recognised units of area.
It is also used to measure the interaction of a nucleus with an electric field gradient in nuclear quadrupole and magnetic resonance.