Door Hardware - Handing Left or Right?
If you are standing at the door to your home, and are going inside, you are on the OUTSIDE of that door.
If you are in a hallway, looking at your bedroom door, you are on the OUTSIDE of that door.
If you are standing in a bedroom with a bathroom attached, you are standing on the OUTSIDE of the bathroom door.
If you are in your garage and going in to your home, you are on the OUTSIDE of that door.
Now for the easy part ...
Stand on the OUTSIDE facing the door. Whichever side the hinges are on determines the door handing. If the hinges are on the right, it's a right hand door. If the hinges are on the left, it's a left hand door. If the door swings out toward the outside then the handing is left handed reverse or right handed reverse depending upon which side hinges are on.