One in five web users have no idea what the download limit on their broadband package is, says Broadbandchoices.co.uk.
Research by the broadband comparison site revealed that 23 percent of Brits were unaware an 'unlimited' download package usually comes with a fair usage policy.
Furthermore 85 percent said it was unfair to advertise an 'unlimited' download package when in reality it came with fair-usage or traffic-management restrictions.
According to Broadbandchoices, 29 percent of web users said their ISP did not explain their traffic management policy when they purchased their broadband package.
Meanwhile, 42 percent admitted they didn't know how much content they download each month.
Michael Phillips, product director at Broadbandchoices.co.uk, said: "Fair usage policies and download limits are fast becoming the next big grievance between consumers and ISPs and this is mainly due to a lack of understanding around the issue.
"The rules governing fair usage policies and download limits need to be taken out of the small print and made clear and easy for everybody to understand."
Phillips also said that while broadband users should take responsibility for their downloading habits and find out what the rules are, ISPs also need to do more to raise awareness of this issue, particularly with the Easter holidays fast approaching.
"When kids are at home there tends to be a peak in online content streaming and parents need to ensure they avoid any unexpected excess usage charges."