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Other than runs scored off the bat from a no-ball, a batsman is not given credit for extras and the extras are tallied separately on the scorecard and count only towards the team's score. A game with many extras is often considered as untidy bowling; conversely, a game having few extras is seen as tidy bowling.
An umpire may call a no-ball when the bowler or fielder commits an illegal action during bowling.
The most common reason for a no-ball is overstepping the popping crease with the front foot. A rarer reason is when the bowler's back foot touches or lands outside the return crease. Other reasons include when a bowler throws (or chucks) the ball, or bowls a full toss above waist high, or for dangerous or unfair short pitched bowling.
The penalty for a no-ball is one run (or, in some one-day competitions, two runs, and/or a "free hit"); furthermore, the no-ball does not count as one of the six in an over and an extra ball is bowled.
The run awarded for the no-ball is not credited to an individual batsman's score but is tallied separately as part of the team's score. Any additional runs scored by the batsman off the bat, whether by running or by a boundary, are included in the individual's score.
It is possible for a team to score byes or leg byes (but not wides) from a delivery ruled a no-ball, these are in addition to the run awarded for the no-ball.
Since the 1980s a no-ball has been scored against the bowler, making the bowling statistics more accurate.
A ball being delivered too far from the batsman to strike it, provided that no part of the batsman's body or equipment touches the ball, is known as a wide.
When a wide is bowled the batting team are awarded a run, which is tallied separately on the scorecard and does not count towards the individual batsman's score. Additionally, a wide is not counted as one of the six balls in the over and a replacement is bowled. All wides are all added to the bowler's score.
If the ball is not struck by the batsman's bat (nor connects with any part of the batsman's body) the batsmen may still run if they choose. If the ball reaches the boundary, whether or not the batsmen ran, four byes are awarded. Any runs scored are tallied separately on the scorecard and do not count towards the batsman's individual score.
Byes may be scored from no-balls as well as from legitimate deliveries.
In modern cricket, byes are normally scored against the wicket-keeper in their statistics.
If the ball hits the batsman's body, then provided the batsman is not out leg before wicket (lbw) and the batsman either tried to avoid being hit or tried to hit the ball with the bat, the batsmen may run. In this case, regardless of the part of anatomy touched by the ball, the runs scored are known as leg-byes. If (with the same provisos) the ball reaches the boundary, whether or not the batsmen ran, then four leg-byes are awarded.
Leg-byes can be scored from no-balls or legitimate deliveries and are counted only towards the team's score, not that of the batsman.
Unlike no-balls and wides, byes and leg-byes are not scored against the bowler.
As well as the runs scored as penalties for no-balls and wides, penalty runs are awarded for various breaches of the Laws, generally related to unfair play or player conduct. Many of these penalties have been added since 2000. Penalties are awarded under Law 41 for Unfair Play  and, since 2017 under Law 42 for Players' Conduct 
Five penalty runs are awarded to the batting team if
Five penalty runs are awarded to the fielding side if the batting team:
The penalty runs are added to the fielding team's score in their previous innings, unless they have not yet batted, in which case the runs are added to their next innings.
Either team may be penalised five runs if the umpires decide that the team have illegally changed the condition of the ball, known as 'ball tampering'.
Either team may be penalised five runs after warning for practising on the pitch on match days, on the rest of the square unless authorised by the umpires, or on the outfield during play except by the fielders, who can only use the match ball, and must not change its condition or waste time.
Law 41 contains a final catch-all (Law 41.19) which empowers the umpire to award five penalty runs for any action that he judges unfair, which is not otherwise covered.
Under Law 42 five penalty runs are awarded to either team if the umpire judges the conduct of their opponents unacceptable. For Level 1 offences the umpire will warn the offending team first, and award penalties on any repeat occurrence by the same team. For Level 2 offences no warning is given. After any Level 2 offence, or any Level 3 ("yellow card") or Level 4 ("red card") offence, no warning is given before awarding penalty runs for any further Level 1 offence by the offending team.
Level 1 offences are:
Level 2 offences are:
Examples and references for each
Examples of some cases are rare in professional cricket to date. One reason for this is that such an award on the pitch by the umpires will be a judgement of a wilful act, and hence of cheating, which the umpires are unable to determine conclusively at the time, or prefer to be made by the Match Referee at more leisure. Some of the recent Law changes are specifically intended to curb deteriorating behaviour in recreational cricket and hence address the retention of umpires 
Some examples of penalty runs are: