The TUC said that a crippling combination of public service cuts, benefit changes and below-inflation pay rises will leave the typical UK family feeling worse-off by nearly £5,000 a year.
An average-income single parent living in London with two children will lose the most, according to the report, with their spending power reduced by 10%.
Meanwhile, a high income, two earner family, living in the South East with three children, will lose the least - 6% of effective income.
© n/aTough choices: Many households may soon have to forgo luxuries like a bottle of wine with dinner
The Unhappy Families study, published ahead of next week's TUC Congress in London, warned that living standards had fallen more than at any time since the 1970s.
TUC General Secretary Brendan Barber said: 'People should be angry at the effect that the crash and Government policies are having on living standards.
'The wrong people are paying the price for what went wrong over 30 years and the coalition's naive belief that they can put right the damage in just four years.
'As experts worry about a double-dip recession it is time to change course to invest in jobs, growth and getting the economy moving. This is the only sure way to repair the damage done by the crash.'
The TUC said it was assuming that wages will go up in line with the Government's projections, took into account the likely effects of RPI inflation, and changes to tax credits and child benefits.
The union organisation said it had also worked out the value of the public services being cut which were used by different families.
Comment: This is currently happening not only in UK, but France, Italy, Portugal, Spain, ...