20 overs per side. 6-over powerplay. Each bowler bowls maximum 4 overs. Strategic timeout. Super Over for ties.
Details
T20 Internationals are played with 20 overs per side. Each bowler can bowl a maximum of 4 overs. Fielding restrictions apply: during the 6-over powerplay, a maximum of 2 fielders can be outside the 30-yard circle; for the remaining 14 overs, maximum 5 outside.
A strategic timeout of 2.5 minutes is taken between overs 6-9 of each innings. This was introduced for TV advertising but also serves as a tactical break.
The time limit for an innings is 90 minutes. If a team falls behind the required over rate, an additional fielder must come inside the 30-yard circle as a penalty.
If the match is tied, a Super Over is played. If the Super Over is also tied, subsequent Super Overs are played.
Historical Evolution
The first T20I was played between Australia and New Zealand at Eden Park, Auckland on February 17, 2005. The format was initially viewed skeptically but grew rapidly after the success of the first T20 World Cup in 2007 and the launch of the IPL in 2008.
T20 cricket has transformed the sport commercially and in terms of playing style, with innovations like switch hits, ramp shots, and new bowling variations.
Current Rule
20 overs per side, 4 overs max per bowler, 6-over powerplay, 90-minute innings time limit, Super Over for ties.