As a complete and utter nerd with no life, one thing that has always puzzled me is the birth dates of the various ponies we've encountered in the show, especially the ones whose birthdays have been mentioned or shown in the show itself. However, today I have nailed down Twilight Sparkle's exact birthdate, using evidence from the show itself as well as from real life and Equestria Girls: Friendship Games.

Twilight's Birthday ("Friendship Games" Evidence)

Zoom out from Friendship Games sticky note EG3
Taking a look at Twilight's calendar from the start of Friendship Games, we notice a few things. First of all, the current date (the day before the Friendship Games) is the 9th of an unknown month. Second, the month has a minimum of 30 days, as there is a birthday cake marking the 30th of that same month. And finally, we now know that Twilight's birthday is likely the 30th of this month (since characters in cartoons rarely mark the birthdays of other people on their own calendars).

Twilight's Birthday ("Sweet and Elite" Evidence)

In Sweet and Elite, Rarity has to chose between Twilight's birthday and the Canterlot Garden Party, a celebration taking place during Spring where the Royal Canterlot Gardens are opened to the public. During the episode, it is mentioned that the Grand Galloping Gala is coming up, meaning that Twilight's birthday is:

  1. During Spring
  2. Before the Gala

But when is the Gala?

The Grand Galloping Gala ("The Ticket Master" Evidence)

In The Ticket Master, Spike reads Celestia's invitation to the Gala, which mentions that it takes place on the "21st of..." before Spike trails off and skips half of the letter. In the same episode, it is mentioned that all of the flowers in the garden bloom at once during the Gala, likely meaning that the Gala takes place during early Spring, meaning that the date of the Gala is either the 21st of April or the 21st of March.

Putting it all together: Twilight's Birthday

We know that Twilight's birthday happens during Spring (March 20th - June 20th), and happens before the Grand Galloping Gala (March 21 OR April 21). In addition, we know that it happens on the 30th of a month. The only date that is possible for this to work is March 30th, 3 weeks and a day before the Grand Galloping Gala on April 21st.

Twilight's birthday is on the 30th of March!