Microsoft is predicting that two-thirds of all of business users of Office will be accessing the software via Office 365 within two years.
The prediction, first reported by ZDNet, was made by Microsoft's head of Office business, Rajesh Jha at the Deutsche Bank technology conference in Las Vegas early last month.
"We have ... about 50 percent of our commercial Office [users] in the cloud with Office 365," Jha said.
"By FY19 we think we'll be about two-thirds of our way there [in terms of commercial Office] customer transition to the cloud."
In the same period, Jha also predicted that business adoption of the company's hosted Exchange services would be even greater, at around 70 percent of all business users.
Jha said that currently there are currently over 100 million active business users of cloud-based Office, which they accessed via multiple operating systems including Windows, iOS and Android.
He said that the attraction of shifting from on-premises to cloud-based Office was in part that it was easier to take advantage of some of the more advanced features added to the package.
"Today there are many segments where you take the sophisticated capabilities that many vendors produce, it's hard for our customers to go stand those things up and be able to consume it, even if they find the capital overlay for it," Jha said.
Despite the increasing cloud adoption, Microsoft will continue to provide standalone variants of its Office for customers who are not yet ready to move to the cloud.
The company announced that Office 2019 standalone will be released next year, and include updated versions of Word, Excel, PowerPoint, and Outlook as well as Exchange, Sharepoint and Skype for Business servers.
However, even users of standalone Office versions will be required to connect to the Office 365 cloud services by 2020, Microsoft said.
Only the most recent version of Office that's available in 2020 will be able to connect to Office 365, effectively forcing users to upgrade their productivity suites.