Calls to businesses or services using freephone numbers will be free from mobile phones as well as landlines, telecoms regulator Ofcom has said.
Under the plan, calls to 0800, 0808 and 116 numbers will always be free.
The move is one of a number of changes announced by the regulator affecting calls to businesses or services.
Ed Richards, Ofcom's chief executive, said the changes would be "the biggest for UK telephone customers in more than a decade".
The changes will be made in June 2015, and Ofcom said it would develop a campaign for consumers to explain in more detail how the changes will work.
Callers to 08, 09 or 118 numbers will be told how much their call will cost, broken down into an "access charge" and an additional "service charge". This will be highlighted on customers' bills and callers may also be told by a recorded message.
Phone companies will set their access charge, while the business or service will control the service charge. This will, in theory, promote competition between the phone operators as customers will be able to compare the rate of their access charges.
Mobile phone companies currently have different access charges for different numbers, and these are not made clear on customers' bills. They also vary considerably.
Currently if someone chooses to call a game show or votes on a reality television programme and the call comes from a BT landline, there is a message explaining how much it costs. But there is no specific information if you call from other service providers or mobiles.
Ofcom says that currently callers are given a message such as: "Calls will cost X pence per minute from a BT line. Calls may vary from other landlines and calls from mobiles may cost considerably more."
Under the new pricing structure, Ofcom said that the message could be revised to say something like: "Calls will cost X pence per minute, plus your phone company's access charge."
Ofcom said that this would help consumers to see on their bills how much their phone provider is charging them, and make it simpler to compare this with others.
Call charges on premium rate - 09 - numbers are to be capped, and Ofcom says "confusion" over numbers starting with 0845 will be addressed by giving a simple breakdown of the "access charge" and the "service charge" as with other numbers.
Ofcom also said that it would also simplify tariffs for calls to 03 numbers, which must now be included in the inclusive minutes or other promotional offers a phone user might have.
Matthew Howett, a telecoms analyst from the researchers Ovum, said consumers should benefit.
"This simplification should be beneficial in terms of the relationship between mobile operator and customer in the long run, particularly considering that many consumers are going mobile-only, and may not have a landline to make freephone calls."
He added that this was not the first instance of such a decision being made by a regulator.
"Similar moves have been made in other countries around the world such as in Australia. Generally consumers in the UK are regarded as getting a good deal and either paying less each year for the telecoms services, or spending the same amount and getting a dramatic increase in quantity and quality of service."