The East Londoners currently have over 20,000 season ticket holders and the most they have sold in one season is 26,000.
When they move there will also be the option to increase the Olympic Stadium capacity to 66,000 in the future.
And judging by latest figures, the Hammers may well need to after it was revealed the club has already sold more season tickets than ever and are closing in on at least 40,000 fully paid up fans with eight months of sales still to go.
'We're on track to make those numbers absolutely'
"At the moment we have 20,000 season tickets approximately and we're moving to 35,000 and hoping to get to 40,000 season tickets.
"Obviously with the season tickets being gone that then allows us to have a much more fluid match by match experience and they're going very well so we're on track to make those numbers absolutely.
"Hospitality is doubling from 2,000 to 4,000 and we're sold out in all but one lounge so we're very pleased."
Barnard is a woman who knows what it takes to handle a big stadium move.
She was at Arsenal during their major growth period which saw them leave Highbury for the Emirates in 2006.
So what did the Hammers do? They went out and poached Barnard from the North Londoners and appointed her as commercial director to help oversee what is arguably the most important phase in the club's history.
Figures make a mockery of predictions
When away tickets, which will average at around 4-5,000 allocation per game, are taken into consideration, it means West Ham will have less than 9,000 tickets for any given match day.
The figures make a mockery of ill-informed predictions from pundits and rival fans that the Hammers would struggle to fill their new home.
And it also begs the question of when and not if the Hammers bump it up to 66,000 to increase revenue and grow the club even further.