It is almost impossible for anyone to work out how much they will receive under the new system introduced last year, according to pension professionals.
The single state pension was supposed to replace a myriad of rules and make it easier for people to understand their entitlement.
Yet the system is actually more complicated, say experts.
Under the system, workers must have at least 35 years of NI contributions – five years more than the previous system – to receive the full payout of £159.55 a week.
People who ‘contracted out’ or took career breaks payouts may not understand that their income could take a hit.
Workers may not realise that they contracted out if they opted not to receive the second state second pension or State Earnings Related Pension Scheme (Serps) in exchange for paying a reduced rate of NI.
Anyone who may not receive the full amount has been urged to top-up the state pension.
Steven Cameron, pensions director at Aegon said: “The new single state pension was presented by the Government as simpler than the old system, but if anything how much an individual will receive will be even more complex to calculate until after a transitional period of decades.
“The previous set up involved a basic state pension and for employees, an earnings related top-up.”
Mr Cameron added: “They or their employer could choose to give up or ‘contract out of’ the earnings related part in return for part of their National Insurance contributions being paid into a private or workplace pension to boost their entitlements there.
“During the lengthy transition period, it is almost impossible for an individual to work out for themselves what they are entitled to.
“So it’s very important to ask for a projection of what you’ll receive from the Department for Work and Pensions.
“This can avoid a nasty shock at state pension age and more importantly allow individuals to work out how much of a private pension they need on top of their state pension to meet their future retirement needs.”