This calculator can be used in order to determine how many liters of sugar syrup you get for a specific quantity of sugar.
http://www.apiarybook.com/sugarsyrup.html
“We consider it as self evident that if the bees store honey for their own use, then honey is what they want and need. Sugar syrup is, at best, a poor substitute. Therefore, we strive to leave enough honey in the hive for the bees’ winter feed”. Phil Chandler