The original, round, 50-cent coin was made of 80% silver and 20% copper; but as the value of a free-floating silver price became higher, the coin's bullion value became more valuable than its face value; so that version was withdrawn from circulation and replaced with the dodecagonal cupro-nickel version.

With a diameter of 31.65 millimetres (1.246 in) across flats,[1] the 50-cent coin is one of the largest in volume among those currently circulating in the world.

Fifty-cent coins are legal tender for amounts not exceeding $5 for any payment of a debt.

A unique effigy by Vladimir Gottwald was used for the 2000 royal visit commemorative fifty-cent piece.

[13] The Australian fifty-cent coin was the first to display a variation of the reverse design in 1970 for the commemorating the bicentennial of Lieutenant James Cook's landing in Australia.