People would need to save £800 a year for 125 years to fund the cost of dementia care, according to a new report.
The study, for the Alzheimer's Society, warns the "impossible cost" of social care is crippling some families and leaving them destitute.
It said the bill will topple "generation rent", who have fewer assets than previous generations, and are at higher risk of developing dementia as people live longer.
A poll of more than 2,300 adults aged 16 to 75 for the charity also found 47% have not started saving for the care they might need in the future.
It comes as one family told how they spent more than £500,000 over 10 years on dementia care after they were found to be ineligible for state-funded help.
Judith Jordan, 48, from Ashtead in Surrey, initially cared for her mother, Joan, who was diagnosed with Alzheimer's disease in her early 60s.
Joan (pictured, left) was able to live at home for a few years until her care needs grew, she kept going missing and was not eating or drinking properly.
Aged 65, she moved into a care home and cashed in stocks, shares, her husband's life insurance and her pension to help fund care.
She could not move properly, suffered bedsores and epilepsy, and could not speak for the last five years of her life.
But despite five assessments for funding, she was always ruled ineligible for state-funded help.
When she died in August 2016 aged 76, Joan weighed just over 4.5st and was paying £4,000 a month for her care.
Mrs Jordan said: "My mum ended up spending over £500,000 on her dementia care.
"She would be devastated to know her money was gone and she could only leave her grandchildren a fraction of what she had hoped.
"She was so proud to think they would be sorted financially in the future.
"By the end of her life mum couldn't eat, drink, speak or move anything but her eyes, yet she still wasn't applicable for state funding despite paying taxes and National Insurance all her life.
"She paid for all her care right until she passed away."
In the poll for the Alzheimer's Society, 54% of adults said the Government should pay for their care and support if they develop dementia, while 5% disagreed.
One carer also told how care at home for people with dementia is severely lacking.
They said carers "couldn't always feed them in the time they had, so very often they (parents) hadn't either eaten or drunk.
"They (carers) didn't always have time to change the bedding.
"They would either forget to do the meds or miss the meds. One time there was a note left to say, 'Derek, this is your meds' and he'd never in a month of Sundays remember."
Rob Burley, director of policy at Alzheimer's Society said: "We have heard of deeply troubling cases where people affected by dementia have had to empty their bank accounts and sell their home to foot a tremendous bill for social care.
"This is simply not fair.
"Other diseases are supported by the NHS, yet people with dementia fall into a void and feel abandoned by the state."
Jeremy Hughes, chief executive of Alzheimer's Society, said: "Getting dementia shouldn't mean families are left bankrupt or destitute with nothing to leave behind.
"The social care crisis is a dementia crisis.
"Many people with dementia and their families are buckling under the inordinate pressure of propping up a failing social care system that has been starved of funding for decades.
"Too many people are forced to give up everything they own in order to care day in and day out for their mother, father, husband or wife.
"I challenge the next government to create a long-term, sustainable system for funding dementia care."
Copyright (c) Press Association Ltd. 2017, All Rights Reserved. Pictured - Joan (left) with Skye, 9. Joan, who was diagnosed with Alzheimer's disease in her early 60s, ended up over £500,000 on her dementia care (c) Judith Jordan / PA Wire.