| 82.1 mm * | 0.1 cm | = 8.21 cm | 
| 1 mm | 
| Units of measurement | Length | 
|---|---|
| Nanometre | 82100000.0 nm | 
| Micrometre | 82100.0 µm | 
| Millimetre | 82.1 mm | 
| Centimetre | 8.21 cm | 
| Inch | 3.2322834646 in | 
| Foot | 0.2693569554 ft | 
| Yard | 0.0897856518 yd | 
| Metre | 0.0821 m | 
| Kilometre | 8.21e-05 km | 
| Mile | 5.10146e-05 mi | 
| Nautical mile | 4.43305e-05 nmi | 
