That depends on a number of things:

  • How long you record for
  • The size of the area that you are recording
  • Which record mode you have selected
  • What recording frame rate you selected
  • What sort of content you are recording (for example, is it a video game or a static desktop)
  • If sound or a webcam recorded as well

Depending on the answers to each of these, the size of your file could vary considerably.