The Liberal Democrats say free personal care would be offered to older or disabled people at home, if they were the government.
Leader Sir Ed Davey says this pledge, plus raising care workers' pay, would end the hospital crisis and help people stay in their own homes.
Plans would be funded by reversing tax cuts given to big banks by the Conservatives, he said, covering the estimated £2.7bn cost by 2028-29.
The numbers are still being assessed, but independent experts suggest the potential costs of this policy are likely to be higher.
The party wants to tackle the huge shortage of care workers by introducing a carer's minimum wage, at a rate £2 above the standard minimum wage, and creating a Royal College of Care Workers comparable to the Royal Colleges of Nursing and Midwives.
Sir Ed, who is a carer for his disabled son and cared for his sick mother when he was young, said the issue was "deeply personal".
Speaking to the OceanNewsUK he said: "I want the party to be the voice of carers, partly because I've been a carer most of my life."
Announcing the policy, he said he was putting the issue "at the heart of the Liberal Democrat offer" to help people live "independently and with dignity", in their own homes wherever possible.
“Far too often, family carers are being left to pick up the pieces because the care system simply isn’t there for them," he said.
“We cannot fix the crisis facing the NHS without fixing the crisis facing social care."
Currently only those with an income and assets under £23,250 get help with the costs of care at home or in residential and nursing homes in England – the least generous system in the UK.
Adult social care charging reforms - including an £86,000 cap on the amount anyone in England has to spend on their personal care over their lifetime - had been due to be implemented by the Conservative government from October 2023 but were delayed by two years.
The Lib Dems would introduce free personal care – a similar system to the one that operates in Scotland.
It would cover costs like nursing care and daily support, including hygiene and medication, for older and disabled people with high needs.
Those needing residential care would still have to contribute towards their accommodation.
The party claims this will ease NHS pressures, picking up issues earlier and freeing up 12,700 hospital beds currently taken up by patients who could be discharged.
They also say it would save the NHS up to £3bn through reduced pressure on hospitals and other NHS services.
While the proposal has largely been welcomed by care industry bodies, they warned that the funding may not be enough to deal with the sector's financial and staffing problems.
Prof Martin Green, chief executive of Care England, which represents adult social care providers, said the Lib Dem policy was "encouraging", but added: "There's no shying away from the fact our sector needs substantial investment."
Sarah Woolnough, chief executive of health policy charity The King's Fund, said that while the proposal would represent a "significant step forward" if implemented, it "will not cover everything that is needed to put social care back on a sustainable footing".
Both Caroline Abrahams, director of charity Age UK, and the Royal College of Nursing said they support the plan - but argued there was currently not enough trained staff in the workforce to fully implement it.
While Mike Padgham, chair of the Independent Care Group, which runs providers in York and North Yorkshire, welcomed the proposal, he called for "true, root and branch reform of social care, which requires the creation of a National Care Service, to bring NHS and social care under one roof and better investment into social care to make that possible".
Labour set out plans to create a national care service in 2023, although shadow health secretary Wes Streeting told the Yorkshire Post last week he would not commit to "jumping straight in with the legislation" in their first term, if they win. The Green Party supports Labour's idea.
Labour have also pledged to create Neighbourhood Health Centres to allow more care services to be provided locally.
The Conservatives have promised to build 100 new GP to help patients get the care they need and relieve pressure on hospitals.
