The former racing tipster likes a punt and has proved naysayers wrong in the past so it's unlikely to be a stab in the dark.
Mr Salmond is a shrewd tactician and he'll be aware that the referendum debate has reached far beyond the chattering classes.
It could be argued that people in Scotland haven't been this politically engaged since the 1980s.
And that appears to have led to an increase in the number of people signing up to vote. The most recent figures released by the Electoral Commission show that 4.1 million are now on the electoral roll.
Between December 2012 and March 2014, an additional 60,000 signed up to have their say on the country's future and around 92,000 of 120,000 16 and 17-year-olds who are eligible to vote for the first time have now registered.
But time is running out for thousands of people who are yet to sign up. The Electoral Commission has set a September 2 deadline.
To ensure a credible result in the referendum, it is vital that as many voters as possible take part.
If Alex Salmond's turnout prediction comes to pass, it will rightly be celebrated as a measure of a healthy democracy.
It will be a welcome change in trends which have seen turnout fall from almost 60% in 1999's Scottish Parliament elec- tions to 50% in 2011's poll.
The decline has been sharper in the Scottish council elections, from a 58% turnout in 1999 to 39% in 2012. So an 80% turnout on September 18 would be sensational.
However, it's also essential that most people in Scotland ensure they are registered to vote.
WHETHER the country decides to remain part of the United Kingdom or go it alone, there must be a clear mandate.
Politicians don't like to be reminded that landslide victories delivering parliamentary majorities do not necessarily indicate overwhelming support.
Tony Blair's famous 1997 victory was achieved with fewer than 14 million votes and David Cameron swept to power in 2010 with just over 10 million ballots cast for the Conservatives.
When Alex Salmond delivered Scotland's first majority government in 2011 he won the support of 45% of voters on a 50% turnout.
Polls suggest the referendum could be close so, to ensure a unity of purpose, whatever the result, as many people as possible must register to vote before September 2.
The winning side must be given a resounding endorsement to credibly claim the support of most people living in Scotland.