DFA

NFA 

Stands for Deterministic Finite Automata.  Stands for Nondeterministic Finite Automata. 
Only one transition for every input symbol at every state.  May have several transitions for every input symbol at every state. 
It can not accept empty strings.  It can accept empty strings. 
Backtracking is allowed in DFA.  Backtracking is not allowed in NFA. 
Only one next state.  The number of next states is zero or one or more. 
Difficult to construct.  Very easier to construct. 
Sequential computation.  Parallel Computation. 
More space required.  Less space required. 
String accept it transit to final states.  If at least one of all possible transition end in final states. 
It can be understood as one machine.  It can be understood as several little machines that compute together. 
All DFA are NFA.  Not all NFA is DFA. 
Require less time for execution  Require more time for execution. 
 Fig(1): DFA 
  Fig(2): NFA 
