Child Tax Credit and Working Tax Credit help to support families with children and working people on low incomes. Child Tax Credit supports families with children and young persons aged from 16 but under 20 years old. You can claim whether or not you are in work. All families with children, with income of up to £58,000 a year (or up to £66,000 a year if there is a child under one year old), can claim the credit in the same way. Working Tax Credit supports working people (whether employed or self-employed) on low incomes by topping up earnings. Child Tax Credit and.