As known, every combination in poker includes five cards. However, in poker combination different amount of card might be used - from one to five. For example for one pair you need just two cards, for two pairs  - four cards etc. So, how to use cards which has no use in poker combination? First of all, let's check poker terminology then we will know that the rest of five cards in some situations will be used as a kicker. And what is a kicker according poker vocabulary? 

That is, in case of equal combinations the pot will belong to that player who has higher kicker. It should be borne in mind following:

• kicker in poker considers only in case of combinations consisting four or less cards. In poker combinations consist five cards (all kinds of straights and flushes) it does not play any role and pot will be divided equally in case when two or more players get same combination;
• as a kicker could be used not just one but more unused cards Their number determined by the difference between common cards (usually there are five cards in poker) and cards including in poker combination. Thus, one pair may have three kickers, set - two, two pairs or four of a kind - just one. 

Combination with one kicker

Let's consider situation. First player holds pocket cards such as:

Second player:

And the board looks like this:

In this case both players has “four of the sevens”.  But first player holds top card face value as ten and second has King as top card. Therefore, taking into account kicker the strongest combination is in second player’s hands.

Combinations with two kickers

Let’s look into another example. 

First player:

Second player:

On the board is combination as following:

Such combination of a board cards and pocket cards gives both players poker combination as  “pair of sevens”.  At the same time both players have a King as a kicker in poker. But first player has a Queen as second of pocket cards and second player holds a Jack. Therefore, the strongest combination is with Queen as a second kicker. Kicker is rated similarly in combination with other sets of cards.

Situation on poker table varies as dealer opens board cards. On each “street” player must consider the existence of one or another card in opponents hands to evaluate the alleged strength of their hands. But it is impossible to get correct estimate if you don't know poker rules about how to use kicker.