The Russian system was based on human sizes, using measures such as sazhen, verst, pyad, and vershok for distances of various sizes. The system varied over time, with different measurements being used, but it was ultimately standardized by Tsar Nikolay the First's 1835 edict "About Russian system of measures and weights".
This edict established a uniform measurement system where one geographic mile was equivalent to 1/15th of an equatorial degree, with a mile comprising of 7 versts, a verst comprising of 500 sazhens, a sazhen comprising of 3 arshins, an arshin comprising of 4 quarters (pyads), and a quarter comprising of 4 vershoks. The system was linked to the British imperial system, with one sazhen equating to 7 feet.
The calculators can be used to convert units of length between the old Russian and metric systems. It is worth noting that the Russian system of measurement ceased to be used on July 21st, 1925, when the Soviet Union adopted the metric system.