The Olympic 100 metres competitions are carried out under standard international rules, as set by the International Association of Athletics Federations (IAAF).
The races are segregated by gender, with one for men and one for women.
The 100 m is usually held at the beginning of the Olympic athletics programme as this allows athletes to compete in other events held later at the games – many 100 m athletes also compete in the 200 metres and the 4×100 metres relay events.

Traditionally there are four rounds of competition: heats, quarter-finals, semi-finals, and finals.
Prior to 1964, finals featured six athletes.
For all Olympic competitions from 1964 onwards—allowing for a sufficient number of athletes being present—each race features eight runners.
Athletes are seeded by past performance to ensure an even balance of quality across the heats and allow the best runners to progress to the later stages.
Usually in the first two rounds the top three runners progress to the next stage.
A small number of other athletes also progress as the fastest non-qualifiers (or "fastest losers") through a repechage system.
Prior to 2012, the semi-finals stage comprised two races of eight athletes and the top four finishers in each race (regardless of time) were entered into the final.

Several amendments were made to the competition format in 2012.
Any participant not in possession of an Olympic qualifying standard time is entered into the preliminary round.
Qualifiers in this round progress to the first round proper.
The semi-finals stage is divided into three races: the top two progress to the final by right and the two fastest non-qualifiers complete the eight finalists.
Changes to the international false start rules were also introduced – any validly recorded reaction time to the starter's pistol of below 0.1 seconds will result in instant disqualification.
At the 2004 and 2008 Olympics one false start was allowed per race, with any subsequent false start resulting in disqualification for the offending athletes.
At Olympics prior to 2004 each athlete was allowed one false start, with a second false start leading to removal from the field.

The top three finishers in the final are awarded a gold, silver and bronze medal, respectively.
If runners cannot be separated by their time (recorded to one hundredth of a second) further analysis is used to distinguish their times to the thousandth of a second.
In the 2008 Women's 100 m final the minor medallists Sherone Simpson and Kerron Stewart could not be separated by this method and were both awarded the silver medal.
Medal positions in a 100 m race have only been shared on one other occasion in Olympic history: Alajos Szokolyi and Francis Lane were joint third at the 1896 men's final.
If it is subsequently found that an athlete broke the competition rules then the IOC may strip athletes of their Olympic medals.
This has occurred twice in the 100 m: Ben Johnson was awarded gold at the 1988 Seoul Olympics, but was soon disqualified after his post-race drug test was positive for banned substances.
The 2000 women's Olympic champion Marion Jones held her medal for a longer period, and was only disqualified seven years later after admitting to doping during that period.
The Olympic 100 metres competitions are carried out under standard international rules, as set by the International Association of Athletics Federations (IAAF). The races are segregated by gender, with one for men and one for women. The 100 m is usually held at the beginning of the Olympic athletics programme as this allows athletes to compete in other events held later at the games – many 100 m athletes also compete in the 200 metres and the 4×100 metres relay events.
Traditionally there are four rounds of competition: heats, quarter-finals, semi-finals, and finals. Prior to 1964, finals featured six athletes. For all Olympic competitions from 1964 onwards—allowing for a sufficient number of athletes being present—each race features eight runners. Athletes are seeded by past performance to ensure an even balance of quality across the heats and allow the best runners to progress to the later stages. Usually in the first two rounds the top three runners progress to the next stage. A small number of other athletes also progress as the fastest non-qualifiers (or "fastest losers") through a repechage system. Prior to 2012, the semi-finals stage comprised two races of eight athletes and the top four finishers in each race (regardless of time) were entered into the final.
Several amendments were made to the competition format in 2012. Any participant not in possession of an Olympic qualifying standard time is entered into the preliminary round. Qualifiers in this round progress to the first round proper. The semi-finals stage is divided into three races: the top two progress to the final by right and the two fastest non-qualifiers complete the eight finalists. Changes to the international false start rules were also introduced – any validly recorded reaction time to the starter's pistol of below 0.1 seconds will result in instant disqualification. At the 2004 and 2008 Olympics one false start was allowed per race, with any subsequent false start resulting in disqualification for the offending athletes. At Olympics prior to 2004 each athlete was allowed one false start, with a second false start leading to removal from the field.
The top three finishers in the final are awarded a gold, silver and bronze medal, respectively. If runners cannot be separated by their time (recorded to one hundredth of a second) further analysis is used to distinguish their times to the thousandth of a second. In the 2008 Women's 100 m final the minor medallists Sherone Simpson and Kerron Stewart could not be separated by this method and were both awarded the silver medal. Medal positions in a 100 m race have only been shared on one other occasion in Olympic history: Alajos Szokolyi and Francis Lane were joint third at the 1896 men's final. If it is subsequently found that an athlete broke the competition rules then the IOC may strip athletes of their Olympic medals. This has occurred twice in the 100 m: Ben Johnson was awarded gold at the 1988 Seoul Olympics, but was soon disqualified after his post-race drug test was positive for banned substances. The 2000 women's Olympic champion Marion Jones held her medal for a longer period, and was only disqualified seven years later after admitting to doping during that period.
100 metres at the Olympics