To know whether this is abnormal we'll need to know more about how you use the tablet. What model is it, how long is the battery lasting, how much time does it spend in use (screen on) vs sleeping?
If the tablet spends the majority of the time sleeping with the screen off, with only very light use, this may actually be normal.
If you could post again with more detail of your battery usage we may be able to give a more helpful answer.