长度是一个基本的物理量，可测量两个点之间的距离。它是国际单元（SI）中的七个基本单元之一，仪表（m）是其基本单元。
1 in = 25.4 mm
1 mm = 0.039 in
例子:
将15 英寸转换为毫米：
15 in = 381 mm
| 英寸 | 毫米 |
|---|---|
| 0.01 in | 0.254 mm |
| 0.1 in | 2.54 mm |
| 1 in | 25.4 mm |
| 2 in | 50.8 mm |
| 3 in | 76.2 mm |
| 5 in | 127 mm |
| 10 in | 254 mm |
| 20 in | 508 mm |
| 30 in | 762 mm |
| 40 in | 1,016 mm |
| 50 in | 1,270 mm |
| 60 in | 1,524 mm |
| 70 in | 1,778 mm |
| 80 in | 2,032 mm |
| 90 in | 2,286 mm |
| 100 in | 2,540 mm |
| 250 in | 6,350 mm |
| 500 in | 12,700 mm |
| 750 in | 19,050 mm |
| 1000 in | 25,400 mm |
| 10000 in | 254,000 mm |
| 100000 in | 2,540,000 mm |
规则