The Formulas tab is present but it might as well not be: its only function is Calculate Workbook. The Page Layout is absent, although most of the layout features are available from the Print dialogue, including scaling.
Like Word Online, Excel Online lacks Drawing support.
You can track, accept, and reject changes and add, show, and resolve comments. In keeping with Microsoft’s push for greater and easier collaborative tools across its Office suite, the Online Review tab is fully functional. The same goes for math equations and icons, as well as tons of Excel and PowerPoint features. For example, there’s no Citation manager in Word Online, but you can add Mendeley, SmartCite, and others.
On the plus side, Office Online does include Add-ons, which is quite exciting because many of the missing functions can be added as third-party plugins. That said, none of the Online apps support a Sidebar for layout and navigation. The Tell Me dialogue is also missing in Word, although PowerPoint and Excel both have this handy feature.
