Is zakat on money calculated for each minor child individually if their money reaches the the minimum threshold, or on the total of all their money combined?

The money children receive on Eid or from their parents belongs to them. It is not permissible to dispose of it without their permission if they are adults. If they are not adults, their guardian is not permitted to dispose of it except in a way that benefits them and preserves it. Zakat is obligatory on this money if it reaches the nisab and a full year has passed over it, and each child has their own nisab. It is not permissible to place this money in interest-bearing savings accounts. Rather, it is obligatory to withdraw it and either keep it, invest it, or deposit it in an Islamic bank.