Overtime
Also called: OT, extra hours
Overtime is time worked beyond a defined threshold — commonly a set number of hours in a week, sometimes in a day — which is usually paid at a higher rate than normal hours.
Where it comes from in a rota
Rarely from planning. It arrives through cover: someone picks up an extra shift late in the week and crosses the threshold nobody was tracking. That is why overtime is best watched while the rota is being built, not when payroll runs.
The thresholds differ
Forty hours a week is the familiar figure but far from universal, and some places count daily as well as weekly. Rates and rules vary by country and often by state or sector — treat any single number as a starting point to verify, not a fact.
Cheaper than it looks, until it is not
A few overtime hours are usually cheaper than hiring another person. Persistent overtime is not: it signals the rota is a person short, and it is being paid for at premium rate every single week.