| 991 m * | 3.280839895 ft | = 3251.31233596 ft | 
| 1 m | 
| Natuurkundige eenheid | Lengte-eenheid | 
|---|---|
| Nanometer | 9.91e+11 nm | 
| Micrometer | 991000000.0 µm | 
| Millimeter | 991000.0 mm | 
| Centimeter | 99100.0 cm | 
| Inch | 39015.7480315 in | 
| Voet | 3251.31233596 ft | 
| Yard | 1083.77077865 yd | 
| Meter | 991.0 m | 
| Kilometer | 0.991 km | 
| Mijl | 0.6157788515 mi | 
| Zeemijl | 0.5350971922 nmi | 
