More than a million children in the UK are caring for family members with health problems, new figures show.
Census figures do not show the true picture, says the trust
The study commissioned by The Princess Royal Trust for Carers found a higher proportion of young people were acting as carers than reported by the census.
The trust said the figures should be a "wake-up call" for local authorities that "ignore" young carers' needs.
Carers often take on much more than the household tasks undertaken by many other youngsters, said the trust.
Responsibilities can range from the personal care of a physically disabled adult to making sure a brother or sister who has a learning disability plays safely, said young carers development co-ordinator for the trust, Alex Fox.
Many young people will stay at home to be there for a parent who misuses substances or has a mental illness, he added.
Researchers questioned more than 1,300 young people and found 12% of those
aged between seven and 19 were looking after someone - the equivalent of 1.1m children on a national scale.
The 2001 census found just 225,000 carers in the same age bracket.
Mr Fox said their survey meant children were asked directly about their situation for the first time.
The census was filled in by parents, who may not admit their child is looking after them or taking on a caring role for a brother or sister, he said.
"We believe that only a tiny percentage of young carers are getting the help
they need," he said.
They have called for further research to be commissioned to address the problem.
The study was timed to coincide with a new website developed by the trust for
YC Net provides information and advice for young
carers and professionals, such as teachers.
A spokeswoman for the trust said it also provided youngsters, who can face bullying, miss school and find it hard to talk about their lives, with a safe place to meet others in the same position online.
Among famous names who have been young carers are pop star Ms
Dynamite, who looked after her siblings when her mother was ill, and TV designer
Laurence Llewelyn-Bowen, who became a carer for his mother when she was
diagnosed with multiple sclerosis.