In the United States, full-time hours are in a range.

Part-time workers are often capped at 29 hours per week, due to tax considerations, such as the Affordable Care Act and other benefits. 30 hours is where the "full-time" label is applied there.

A wage-earning (non-exempt) worker must be paid overtime when they exceed full-time, which is typically a 40-hour maximum. Overtime pay may be "time and a half" or "double time" in certain circumstances.

Dolly Parton's feminist anthem "9 to 5" always mystified me: that's already 40 hours! Don't you stop to eat lunch? But that is the standard idiom for a "normal [office] job" in the States. Sometimes we refer to "banker's hours" which has the negative connotation that the worker never ever works outside that schedule.