Many people are still confused about changes to the state pension, which come into force next week, the consumer group Which? has warned.
Nearly half of the 1,000 people surveyed said they did not know what the new rate will be from 6 April.
A new flat rate or single tier state pension comes into force for everyone who retires from Wednesday.
The government said it would be easier to understand and a new pension forecast tool would soon be online.
The current system was seen as confusing and contains a number of different sources contributing to a state pension.
From 6 April, people of state pension age who have made the full 35 years of National Insurance contributions will get £155.65 per week.
Those with fewer years of contributions will get proportionately less, and anyone with less than 10 years of contributions is unlikely to get any state pension.
Which? found that 68% of the 50 to 64-year-olds they surveyed were aware changes are coming in - rising to 80% of those aged between 60 and 64.
But 44% said they did not know what the full rate will be and only one in five knew the state pension age will be 65 for both men and women by the end of 2018.
Usually people will need at least 10 years of qualifying National Insurance (NI) contributions to get any state pension. Being contracted out for even a short period of time could leave people with a much smaller pension than they were expecting.
Only 18% knew if they had ever been contracted out of the state pension.
Women and the self employed are expected to be better off under the new system but younger people may lose out.
Which? executive director Richard Lloyd, said: "While it's promising to see that awareness of the upcoming changes is high, we're only half way there.
"More needs to be done to make sure that people understand what the changes are and what they mean for them."
Pensions Minister Ros Altmann said: "It is vital that people check what their state pension is likely to be, especially when planning their future later life income."
She said it would be easier to understand and a new individual state pension forecast will soon become available online.
"This is in public testing now and in the meantime anyone over age 50 can get a written statement showing their estimated state pension," she said.
Gareth Shaw, head of consumer affairs at Saga Investment Services, said: "The current system is horribly complicated, and the new single-tier will eventually wave away this complexity. But today's generation of state pensioners need more help understanding what they're entitled to."