Full name: hour
Plural form: hours
Symbol: hr
Alternate spelling: hrs
Category type: time
Scale factor: 3600
The SI base unit for time is the second.
1 second is equal to 0.000277777777778 hours.
Valid units must be of the time type.
You can use this form to select from known units:
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The hour was originally defined in Egypt as 1/24 of a day, based on their duo-decimal numbering system (which counted finger joints on each hand).
