How much time would you actually do in Missouri prison if your sentence was 5 years?

This depends on the crime and criminal history. If the crime committed is Robbery 1st or Assault 1st then 85% of the sentence must be served. Sex offenses also require 85%. If the offender has a poor criminal history (2 or more prior felony convictions) then at least 50% or 2.5 years must be served. No priors then release is probable in less than one year. Keep in mind jail time served prior to plea or finding of guilt counts towards the prison sentence.