How does Filmot round a video's age in labels such as "12 years ago"?

Filmot displays elapsed time using complete units, rounded down. For an age expressed in years, a video that is almost 12 years old is shown as 11 years ago; it changes to 12 years ago after 12 full years have passed.

The same approach applies to shorter units, such as months, weeks, days and hours. Use the displayed upload date when you need the precise date rather than a relative age label.