Unit of Measure Conversions
Area Conversions
Additional Units and Information
| Name | Symbol | Value | Description/Notes |
|---|---|---|---|
| are | a | 100 square metres; 1/100 hectare |
|
| centare | 1 square metre | ||
| square chain |
ch² | 484 square yards; 1/10 acre |
|
| circular mil | 7.853982 x 10-7 square inch | The area of a circle with 0.001" diameter. Used in measuring the cross-section of fine wire | |
| hectad | 10 kilometre x 10 kilometre square | Used in British Ordnance Survey mapping | |
| square millimetre |
mm² | 1/100 square centimetre | |
| myriad | 100 kilometre x 100 kilometre square | Used in British Ordnance Survey mapping | |
| square pole |
pl² | 30¼ square yards | |
| rood | 40 square poles; ¼ acre |
||
| tetrad | 2 kilometre x 2 kilometre square | Used in British Ordnance Survey mapping |
Useful Approximations
| Approximation | % Accuracy |
|---|---|
| 1 square yard ≈ 1300 square inches | 99.7 |
| 1 square metre ≈ 1500 square inches | 96.8 |
| 1 hectare ≈ 2½ acres | 98.8 |
| 1 square kilometre ≈ 250 acres | 98.8 |
| 1 square mile ≈ 2½ square kilometres | 96.5 |
| 1 square mile ≈ ¾ square international nautical mile | 99.3 |