Exodus 30:13

Each one who is numbered in the census shall give this : half a shekel according to the shekel of the sanctuary (the shekel is twenty gerahs ), half a shekel as an offering to the Lord .

Each one who crosses over to those already counted is to give a half shekel, according to the sanctuary shekel, which weighs twenty gerahs. This half shekel is an offering to the Lord.

This they shall give, every one that passeth among them that are numbered, half a shekel after the shekel of the sanctuary : ( a shekel is twenty gerahs :) an half shekel shall be the offering of the Lord.