OS-dependent modifier. Unlike desktop Excel (which has dedicated Mac and Windows pages), the Excel web app uses whatever modifier your OS expects: Command on Mac, Ctrl on Windows. The shortcut actions are the same; only the modifier key differs based on your OS. If you switch between Mac and Windows browsers for Excel work, the same mental model applies as for any Mac/Windows shortcut pair.
Browser shortcut conflicts. The browser layer sits between your keyboard and the Excel web app, and some combinations are captured by the browser before Excel receives them. Common conflicts involve shortcuts for closing tabs (Ctrl+W / Cmd+W), opening new windows, and switching tabs, these behave as browser shortcuts rather than Excel shortcuts. The table above notes the most common conflicts.
Feature coverage compared to desktop. Excel for the web supports a wide range of shortcut-accessible features, cell navigation, formula entry, formatting, and basic workbook management. Some desktop-only features and their shortcuts are not available: macros, Power Query, full Ribbon customization, and certain advanced formula functions. The table above covers what is actually supported in the web version.
Accessing Excel for the web. Excel for the web is available at office.com or onedrive.live.com with a Microsoft account, or through a Microsoft 365 subscription.