Metric vs Imperial System
The world uses two main measurement systems: the metric system (used by most countries) and the imperial system (used primarily in the US, UK, and a few others).
The Metric System
Based on powers of 10, the metric system uses:
- Millimeters (mm) for very small lengths
- Centimeters (cm) for everyday measurements
- Meters (m) for room-scale measurements
- Kilometers (km) for distances
The Imperial System
The imperial system uses:
- Inches (in) for small measurements
- Feet (ft) for height and room dimensions
- Yards (yd) for medium distances
- Miles (mi) for long distances
Key Differences
| Metric | Imperial | Conversion |
|---|---|---|
| 1 cm | 0.3937 in | ×0.3937 |
| 1 m | 3.281 ft | ×3.281 |
| 1 km | 0.6214 mi | ×0.6214 |
| 1 kg | 2.205 lbs | ×2.205 |
Why Two Systems?
The metric system was created in France in 1795. The imperial system evolved from English units centuries earlier. Most countries have adopted metric, but the US, Liberia, and Myanmar still primarily use imperial.