Clearer labelling is needed on sunscreens amid what has been described as a worrying lack of understanding about the protection they provide, the Royal Pharmaceutical Society said.
A quarter of people did not know what the rating on their sun protection stood for, and the majority did not know that the Sun Protection Factor (SPF) rating protects them from only some of the sun's harmful rays, according to the poll.
Fewer than half of the 2,057 adults who took part in the YouGov survey last month said they always or often use sun protection.
Both UVA and UVB rays from the sun can cause skin damage and skin cancer. The SPF rating on the product label refers only to the protection level against UVB rays, while a separate star rating usually indicated the protection factor against UVA rays, the society said.
Fifteen per cent of adults with children in their household admitted that they never checked the UVA rating.
Differences in labels are causing confusion among buyers, chief scientist for the Royal Pharmaceutical Society Professor Jayne Lawrence said, as she called for one clear label to be used across all products.
Prof Lawrence said: "This survey indicates that there is a huge amount of confusion around sunscreen labelling that is a barrier to effective sun protection.
"Clearly many consumers do not realise the SPF rating applies only to the amount of protection offered against UVB rays, not UVA rays – both of which can damage the skin and cause skin cancer.
"People should not have to pick their way through complicated dual ratings information to understand how sunscreen works and the amount of protection it potentially provides.
"We think it's time for sunscreen manufacturers to provide one easy to understand rating, based on a simple description of the total amount of sun protection offered: low, medium, high and very high protection.
"People now have largely got the message that they must protect their skin from the sun using sunscreen, along with other precautions such as covering up and keeping out of the sun during the hottest part of the day.
"What the RPS is calling for now is one uniform measure for all sun protection products, so pharmacists can provide easy to understand advice on the effectiveness of products and how they should be used."