Is zakat calculated on the full amount or only on the increase if the wealth grows after the passing of a full year (hawl) and the payment of zakat?

If the saved money reaches the nisab (threshold) and a complete year (hawl) passes over it, then zakat becomes obligatory at the end of its hawl, and it is not permissible to delay it. Zakat is obligatory on the entire amount each year, not just on the increase. If the increase is generated from the original capital, then it is zakatable along with it when its hawl is due, and a new hawl is not started for it. However, if the increase is not generated [from the original capital], then a separate hawl is calculated for it, and it is permissible to pay its zakat in advance along with the original amount.