Commonly used length units are: kilometer, kilometer (km), decimeter (dm), centimeter (cm), millimeter (mm), micron (micron), nanometer (nm), picometer (pm) and femto meter (fm).

The traditional units of length in China are Li, Zhang, Chi, Inch, Xun, Jie, Fu, Zhi, Yi, Bu, Chang, Ya, Yan, Ji, Rail, Luo, Millimeter, Li and Min.

The basic transformation relationship is as follows:

1 ft = 10 ft; 1 ft = 10 inch; 1 inch = 10 points; 1 = 10%.

1 sheet ≈ 3.33m; 1 ft ≈3.33 decimeter; 1 inch ≈3.33 cm.

1km = 1000m； 1 meter (m) = 100 cm; 1 cm =10mm.

1 Li = 150 sheets = 500m; 2 Li = 1 km (1000 m).