Extras change the ball, the score, and the dismissal.

How the umpire checks it

1. Check for no-ball first: front foot, back foot, delivery mode, height, fielding restrictions, and other unfair delivery issues.
2. If it is not a no-ball, decide whether it is wide based on the striker's reach and the competition's wide guidance.
3. Add the penalty run and any completed runs or boundary allowance.
4. Decide whether the ball counts in the over. No-balls and wides normally do not.
5. Apply the right dismissal list, because no-ball, wide, and free-hit deliveries restrict how the batter can be out.

What usually triggers one

• Foot fault: the bowler fails the front-foot or back-foot landing requirements.
• Dangerous height: a delivery reaches the batter at an illegal height under the Laws or playing conditions.
• Illegal delivery: throwing, underarm bowling without agreement, or failing to tell the umpire about a change in mode can produce a no-ball.
• Fielding breach: too many fielders in a protected area can also create a no-ball under relevant playing conditions.

Why reach matters

A wide is not just a ball that misses the bat. The umpire asks whether it passed wide of where the striker stood and would also have passed wide of a normal batting position, beyond the reach of a normal cricket stroke. Limited-overs cricket often applies stricter guidance.

What changes next ball

In many limited-overs formats, a no-ball gives the striker a free hit on the next delivery. The batter cannot be out in most ordinary ways on that ball, but run out, obstructing the field, and a few other dismissal routes can still apply.

Separate the penalty from what happens next

A no-ball or wide begins with its one-run penalty, unless the competition specifies otherwise. Additional completed runs and any boundary allowance are then added. On a no-ball, runs from the bat are credited to the striker; runs not hit by the bat are recorded with the no-ball extras according to the scoring rules. On a wide, every additional run belongs to wides, including a boundary allowance when the ball reaches the rope untouched. Neither delivery normally counts as one of the over's six valid balls, so the bowler must send another legal delivery before the over can end.

The call removes several ordinary dismissals

After no-ball, the striker cannot be out bowled, caught, LBW, stumped, or hit wicket from that delivery. Run out, obstructing the field, and hitting the ball twice can still apply in the circumstances allowed by their Laws. A wide has a different list: the striker can be stumped from a wide and either batter can be run out, but the striker cannot be bowled or caught because the delivery never lawfully contacted the bat. Always classify the delivery first, then test the appeal against the dismissal methods still available; seeing the wicket broken is not enough by itself.

An illegal next ball does not use it up

Under common limited-overs playing conditions, the delivery after the relevant no-ball is a free hit. If that next delivery is itself a no-ball or a wide, the free hit carries forward to the following delivery. Field changes may also be restricted unless the striker changes. A free hit is not immunity from every possible dismissal: dismissals available from a no-ball generally remain possible, particularly run out and obstructing the field.

"It was a wide and a no-ball"

The no-ball call takes priority. If the same delivery could look wide as well, it is scored as a no-ball, not both. That matters for the scorebook, the over count, and any free-hit consequence.

Source material

• MCC Laws of Cricket
• MCC Law 21: No ball
• MCC Law 22: Wide ball
• ICC Playing Conditions