More than seven million people in their 30s and 40s will lose out by £10,000 each under Government plans to increase the state pension age earlier than planned.
People born between 1970 and 1978 will have to wait until they are 68, an extra year, before receiving payments, Work and Pensions Secretary David Gauke announced last week.
Labour said the reforms were "disgraceful and unjustified" and accused the Government of making workers carry on for longer to pay for their failing austerity policies.
Analysis by the House of Commons Library found the £74 billion the move will save works out to £9,800 per person on average across the 7.6 million hit by the change.
The amount is approximately equivalent to around one year's worth of payments of the new state pension, which totals £8,300, the research said.
Debbie Abrahams, shadow work and pensions secretary, said: "This is a disgraceful and unjustified attack on the state pension by this Government, who are asking millions of people to work longer to pay for their failing austerity plans.
"The latest research on life expectancy, published days ago, shows that there is no evidential basis for bringing the state pension age further forward.
"That's why Labour want to take a measured approach, leaving the state pension age at 66 while we review the evidence emerging around life expectancy and healthy life expectancy, considering how we can best protect those doing demanding jobs and the contributions they have already made."
Under current plans, the state pension age for men and women will be equalised at 65 at the end of 2018, before rising to 66 in 2020 and 67 in 2028.
The new change affects anyone born between April 6 1970 and April 5 1978.
The Department for Work and Pensions (DWP) said it would save the equivalent of £400 a year per household.
A DWP spokesman said: "These changes will ensure that the state pension is both fair and sustainable for future generations.
"Those affected will on average still receive the state pension for longer than the generations before them.
"Under the simplified new state pension at its basic level, people in retirement will receive over £1,250 a year more than compared to April 2010."