It appears that ‘Each’ and ‘Every’ have similar meanings and they can be used as replacements of each other. But if minutely seen, there is a difference between them. Let’s understand this difference with the help of examples.
Look at the each face in the photograph carefully.
Here each means one by one and one and one at a time. Each is used mainly when the number is small.

Let’s take another example with ‘Every’.
Every house in the village should have electricity.
Here ‘every house’ refers to all the houses. So every is used when the number is large. Some more examples are.

 There were four books on the table. Each book had a different title. (Number of books is just four)
 A cricket team has eleven players. Each has to contribute to the team’s victory.
 At the beginning of the match, each player of the team has to shake hand with the players of the other team.
 My friend loves reading. He reads every book which he comes across.(Number of books is more)
 Every star in the sky twinkles at night.
 Every voter from my area voted in the last elections.