It's impossible to know that due to the myriad factors affecting battery drain. Cell signal being weak, Wi-Fi and or Bluetooth constantly on, apps syncing, apps not sleeping.. The list is endless.
As a rough guide, if you can get through a day in one charge you are doing OK as a moderate user.
If the device is new, the battery takes awhile to settle as it were. There are many things to do, you can make sure all apps sleep when not open (battery settings), you can restrict background activity (in apps settings), you can put apps to sleep (from developers options)...