Royal Mail is to be valued at between £2.6bn and £3.3bn, the government says.
The Treasury said on Friday that Royal Mail would list on the London Stock Exchange next month. BBC business editor Robert Peston says that the privatisation should be completed by 15 October.
He adds that this is "long before" a possible strike could happen.
Postal workers will start on Friday begin voting on whether to take industrial action to oppose the plan.
It is expected that 10% of the shares, which will be priced between 260p and 330p, will be given to Royal Mail employees.
The government intends to sell between 40.1% and 52.2% of the Royal Mail under its privatisation proposal.
The Communication Workers Union (CWU) is balloting 100,000 of its members on a nationwide strike over the privatisation, as well as on changes to salary and pensions.
Voting will close on 16 October.
Our business editor adds that this is a "very big moment" in the history of the 500-year-old postal service, describing the government's programme as "ambitious".
He adds: "Remember that industrial relations are pretty terrible at the moment, and the government's timetable for this means it is now impossible for there to be a strike before the privatisation is done. It will be in the private sector before there can be a strike."
Source: BBC News - Business http://www.bbc.co.uk/news/business-24294745#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa
