Water weight matters

Water is extremely heavy, even a small aquarium is surprisingly heavy when full. This is why it is important to use a properly constructed aquarium stand which is designed for the job rather than a set of drawers or table top which may collapse or bow causing the tank to crack.

With larger aquariums use a stand which spreads the weight across a large surface of the floor or at least place the stands legs as near to joists as possible so that the floor itself doesn't begin to sag under the weight.

This calculator only gives the weight of the water in the aquarium, you still have to add to this the weight of the tank, substrate, rockwork, stand and top.