The distance between each of an individual’s eyes or better pupils is called interpupillary distance. Most binoculars have an option of adapting the barrels to a specific position to ensure the whole image, either bringing them closer together or further apart. Normally this distance is somewhere between 58 and 75 mm. Often women and children have shorter interpupillary distances, so they must choose between compact binoculars.
The best practice is to try binoculars in person to get the feel of them and see if they suit you.
Source: Optics Trade