Many children are failing to earn interest on their pocket money or wages because they put the cash in a piggy bank instead of a savings account, according to the Halifax.
Half the 1,005 children questioned in a survey said they keep their money in a piggy bank while 6 per cent entrust it to their parents.
Only around a third put their cash in a bank or building society account.
The survey of children aged between seven and 16 shows that boys get an average of £6.18 pocket money each week compared with £5.38 for girls.
Most children aged between 11 and 16 are given £5 a week but one-fifth receive £10. Scottish children get the highest pocket money with an average of £6.28 a week, while children in the South get £5.96 a week.
Nearly a quarter of 11 to 16-year-olds have part-time jobs, earning an average of £27.31. This rises to 58 per cent of 16-year-olds, who on average earn £42.20 a week. Paper rounds are the most popular jobs.
One of the main reasons for having a part-time job may be that more than a fifth of the children questioned own a mobile phone.
Head of savings Nick Robinson says: “There is little doubt that children do extraordinarily well from the amount of pocket money they receive from parents and grandparents. They are not only very good negotiators when it comes to pocket money but they also appear to know the importance of looking after their cash.”