User blog comment:Emily Windsnap/How old are the Merlin characters?/@comment-80.7.103.140-20141202010823/@comment-25243775-20141202164436

I partially agree about Merlin and Arthur. I think that Merlin is 17 in Series One and turns 18 when he dies, because every series lasts around 6 months (Series 1 + Series 2 + 1 year + Series 3 + 1 year = 3 and a half years). Arthur turns 21 in Series One (Excalbur, episode 9). Also, Arthur celebrated his birthday in Series Four (The Wicked Day, 4x03)... it is clear that Arthur's birthday is placed in Spring or in Summer; I assumed it was in March, because the second last episode takes place on April 30/May 1. The first episode is actually place on October 31/April 1, thus Arthur turns 25 in the third episode. The Death Song of Uther Pendragon is placed exactly 3 years after The Wicked Day, so Arthur is 27 at the start of Series Five and turns 28 in the third episode, while Merlin is 24 and maybe turns 25 by the end of the series.