The common shortcut key for redo is:

  • Windows & many apps: Ctrl + Y (sometimes Ctrl + Shift + Z in design or cross‑platform tools)
  • macOS: Command (⌘) + Shift + Z
  • Microsoft Office (Windows): Ctrl + Y or F4 to repeat/redo the last action

In most everyday apps, if Ctrl + Y (or ⌘ + Shift + Z on Mac) does nothing, check the Edit → Redo menu to see the exact shortcut used in that program.