Real age of Justin Bieber in Justin Bieber's Believe
In the movie Justin Bieber's Believe, Justin Bieber was:
18 years old
That was the real age of the celebrity according to our calculation.
The calculation of the shown age took into account the first day of the year in which the movie Justin Bieber's Believe was released:
January 1, 2013
And the day in which Justin Bieber was born:March 01, 1994
Since movies usually don't take more than one year to be released since the beginning of the filming process, Justin Bieber may have been one year younger or one year older than the shown age while some scenes of the movie were being filmed.