A quarter of people retiring between 2016 and 2030 will be worse off under the new state pension rules, according to estimates published today by the Department of Work and Pensions.Most people will benefit from the change to the new system, which grants is worth £155.65 a week to people retiring from April 2016 with 35 years’ national insurance contributions.But those who have not reached the qualifying 35 years’ will not be eligible for the full amount. During the first five years, almost three-in-ten people will receive around £100 less a year on average as a result of the switch. Roughly the same proportion of retirees will be worse off between 2020 and 2030, though the amount they could lose increases over time. Some 30% of people retiring in 2030 will lose £350 a year, on average.The government’s estimates suggest men are a bit more likely to miss out under the new system. Around 30% of men retiring before 2030 will lose out, compared to 25% of women. Vince Smith Hughes, retirement expert at Prudential, welcomes the move to a simpler system, but says working out if you’ll be better or worse of is “incredibly difficult,” due to “the complexity of the component parts of the current system.”“People who are likely to not receive the full amount are those who have contracted out. They may have been in a final salary scheme and not have a full national insurance record.”He recommends requesting a state pension forecast to anyone looking to see what they’ll get when they reach retirement. This can be done at https://www.gov.uk/state-pension-statement. Alternatively, people can seek free guidance from the Pensions Advisory Service, or seek professional advice from an adviser.