Broadband providers will have to ensure at least 50% of customers can receive their advertised headline speeds under proposals to prevent consumers from being misled.
Current standards say speeds quoted in broadband adverts need apply to a minimum of just 10% of all customers, providing they include the words "up to".
The Committees of Advertising Practice (CAP) is consulting on toughening up the standards following research which found they are currently likely to mislead consumers.
The study, commissioned by the Advertising Standards Authority (ASA), found most consumers think they are likely to receive a speed at or close to a provider's headline claim when, for many, that is not likely to be the case.
Previous independent testing by consumer groups has found up to three-quarters of households are paying for advertised broadband speeds they have never received.
As well as the proposed 50% requirement, CAP will also consult on whether consumers would like the headline speed to be presented as a range of speeds or an average speed, and if it should available at peak times or over 24 hours.
Each ad will also have to urge potential customers to check with the provider about the speed they are likely to receive.
CAP director Shahriar Coupal said: "Research commissioned by the ASA persuades us that tougher standards are needed to prevent consumers from being misled by advertised broadband speed claims.
"For the next 10 weeks, we're inviting views on four options for change and remain open to any other options that better-manage consumers' expectations of the broadband speed they're likely to receive."
Gillian Brown, vice-chairwoman of the Local Government Association's people and places board, said: "Good digital connectivity is a vital element of everyday life for residents and can help them cut household bills, shop online for cheaper goods, stay in touch with distant relatives, access their bank accounts and even run their own businesses.
"In its current form, the headline 'up to' download speed, which can be advertised legally, is misleading and does not reflect the reality of broadband service received across the country.
"Broadband users deserve greater honesty and openness about the download and upload speeds they are likely to receive depending on their location."
CAP's consultation closes on July 13.
Digital Minister Matt Hancock said: "I'm delighted that rules on how broadband speeds are advertised are to be tightened up.
"So-called 'up to' speeds that in the past only needed to be available to 10% of consumers are incredibly misleading, customers need clear, concise and accurate information in order to make an informed choice.
"In the past, too many people haven't been getting the speeds they thought they signed up for, and I'm pleased this is being put right."