It depends on the scope of your Project Online environment. Based on PPM Works’ published migration packages, a simple migration (around 100 projects) typically takes about 3 weeks, a medium-complexity migration (around 400 projects) about 5 weeks, a complex migration (around 1,000 projects) about 7 weeks, and larger custom environments (1,000+ projects) 8 or more weeks. A PPM Works Lifeboat Assessment is the best way to scope the exact timeline for your organization.