The NSPCC said Childline – which has been operating for 30 years – had primarily been viewed as a telephone helpline, but last year 71 per cent of children who contacted the service did so online.
The support offered by Childline today includes services such as one-to-one online chats with counsellors, email counselling and access to a community of young people on online message boards and social channels.
The charity said it wanted to ensure that the Childline brand reflected its digital-first approach.
The NSPCC’s in-house creative studio and digital team worked with the digital agency Amaze on the redesign.
"At the heart of the project was the ambition to provide an excellent user experience, designed with, and for, the young people who need Childline the most," according to a statement from the charity.
An NSPCC spokesman said the project had so far taken about two years, including significant time spent on research and testing, although the time spent building the new site was much shorter.
He said the amount the charity had spent on the project was commercially confidential.
Sue Hornsby, creative director at the NSPCC, said: "The challenge for the in-house creative team working on the new brand was that there was a high level of awareness of the Childline service among young people, but too many saw it just as a helpline for those in extreme danger. It was vital that it was given a more universal appeal."
She said the new brand needed to communicate to young people that it was their Childline and their world.
Hornsby said the brand had been designed to create a balance between the "vibrancy of the child’s world and the reassurance the service offers".
She said: "This is summed up by the new strapline: online, on the phone, anytime, which lets young people know that Childline is here for them, however they want to get in touch, whenever they want to talk."