When putting a child in Timeout as a form of discipline which works very well you should put the child in Timeout for 1 minute for every year of the child's age.
So if the child is 2 years old you'd put the child in Timeout for 2 minutes and if they're 5 years old you'd put the child in Timeout for 5 minutes and if they're 8 years old you'd put the child in Timeout for 8 minutes etc.
Just put the child in timeout for a minute for every year of there age.
However if the child is under 2 years old only leave the toddler in timeout until they calm down which usually happens in one minute or less.
Timeouts were very effective on me as a child and they're still very effective if done right today.