New figures from the 2001 Census show that there are nearly 150,000 child carers in the UK, three times more than earlier estimates.
The Children's Society and the Princess Royal Trust for Carers have welcomed the shock figures. But they warn the total might still be too low because parents sometimes don't recognise or admit that their children are acting as carers to other members of the family.
"We're really pleased that the census shows a more realistic view of the situation we're dealing with," said Alex Fox, young carers co-ordinator at the Princess Royal Trust for Carers.
This week, several child carers supported by the charities met with the Parliamentary Under Secretary for young people and learning, Ivan Lewis.
The 2001 Census, the first to include questions about carers, showed that 149,000 under-18s provide unpaid care within their families. This is three times higher than the Office of National Statistics' 1996 estimate.