The contribution of people over the age of 65 is equivalent to 4.6 per cent of the size of the UK economy and six times more than the money spent on social care by local authorities in England alone, says the charity Age UK.
It found £37bn of the total amount came from employment and £11.4bn from informal caring. Child care contributed £6.6bn. Nearly £6bn came from volunteering.
The charity's Chief Economist document, which mainly examines 2012, said for the first time there are now more than eleven million people in the UK aged 65 and over. An increasing number of them - over a million - are working.
Although some will be doing so from financial necessity, many others want to work for longer because they are in good health and because what they achieve at work is valuable and worthwhile, said the charity.
The report also says the bulk of child care undertaken by older people is carried out by those aged 65 and over - most frequently probably grandparents who look after their grandchildren, to enable their own adult children to work.
The charity says this is "an example of the crucial economic and social contribution older people often make, even when they are not in paid employment themselves".
It revealed that outside of London and the south east, the elderly in Scotland contribute more to the economy per hour through their jobs.
They estimate the typical person over 65 in Scotland contributes £1,438 an hour to the economy through employment, with only London (£1,862) and the south east (£1,542) more valuable. But after taking into account, the number of hours worked by the elderly workforce, the report shows those in Scotland contribute proportionally less to the economy through their jobs than the UK average.
Age UK estimates the elderly in the UK contributed 2.83 per cent to the UK economy through employment while the Scots contributed 2.43 per cent to the Scots economy.
The lowest proportion was in Northern Ireland (0.78 per cent) and London (1.98 per cent) and the highest in Wales (4.07 per cent) and the south east (3.61 per cent), reflecting both the number of older workers and the number of actual hours they work, the report says.
Caroline Abrahams, charity director of Age UK, said: "Many will be surprised by just how much older people contribute. It is time we appreciated they are playing a more and more important part in creating our prosperity. Older people bring a great deal of knowledge, skill and energy, as volunteers and as paid employees, and in doing so they are redefining what it means to be 'an older person'.
"With our rapidly ageing population and the rising state pension age it is more important than ever that we consign age discrimination to the past and enable older people who want to continue to work to do so."
Age UK says it is concerned older people who want to keep working still find themselves locked out of the labour market as a result of age discrimination.
More than 113,000 men and 65,000 women aged 50 and over have been out of work for more than a year and are finding it tough to get back into work, the charity said. Many others work part-time when they would prefer to work full-time.
Ms Abrahams added: "Youth unemployment is a serious concern and some may worry older people who work are depriving young people of jobs; however, the economic evidence is clear that employing older workers does not affect the number of jobs available to younger people."