Roblox hotbar size depends on the device: on PC, it typically shows 10 slots , while on many mobile devices it is reduced to 3 slots.

Quick note

  • PC / desktop: usually 10 visible tool slots.
  • Mobile: often 3 visible slots on smaller screens.
  • The hotbar can still hold more tools in the backpack/inventory beyond what is shown.

In plain terms

If you meant the UI size of the hotbar itself, Roblox does not give one fixed universal pixel size because it scales by device and screen size.

If you meant the number of slots , the common default is 10 on desktop and fewer on mobile.

Bottom line

For most players, the answer is: 10 slots on PC, 3 on many phones.