The main difference Between micro sim and Mini Sim is the difference of their physical dimensions.
The SIM ( Subscriber Identity Module ) that are generally of following types:-
1. Full size SIM - Full size sim has their size like a credit card. They are of rectangular shape. The Registration number that we got for our Vehicle is a full sized sim .
2. Mini SIM - Mini sim is derived from the Full size sim but it is only of dimensions 25x15 mm. This are that we often use in our mobile.
3. Micro SIM- Now a days every mobile other than JAVA have their SIM card slots for the Micro sim. they have the dimension 12.30x8.80mm. They have the size of a SD card.
4. Nano SIM-Nano sim only contain the circuit part means the boundary of sim is limited to the size of the circuit.