How many concerts has hatsune miku had?

Answer 1

So far, about 15 concerts/screenings.

Her first concert as a character performing on stage (screen) was in Japan at Animelo Summer Live on 22 Aug. 2009. Her other appearances (in order) so far are as follows:

2) MikuFes '09 - 31 Aug. 2009 - Japan

3) Anime Festival Asia (AFA) - 21 Nov. 2009 - Singapore

4) Miku no Hi Kanshasai 39's Giving Day at Zepp Tokyo - 9 Mar. 2010 - Japan

4) J-Pop Summit - 19 Sep. - San Fransisco, USA

5) New York Anime Festival, J-Pop Summit screening - 9 Oct. 2010 - New York, USA

6) J-Pop Summit encore screening at Viz Cinema - 11 Oct. 2010 - San Fransisco, USA

7) Vocarock Festival - 11 Jan. 2011 - Japan

8) Vocaloid Festa - 12 Feb. 2011 - Japan

9) Hatsune Miku Live Party, Mikupa at Zepp Tokyo - 9 Mar. 2011 - Japan

10) Vocafes2 - 29 May 2011 - Japan

11) Anime Expo 2011 at Nokia Theater - 2 Jul 2011 - Los Angeles, USA

12) Anime Expo - 9 Nov. 2011 - Dusslendorf, Germany

13) Anime Festival Asia, Mikupa show - 11 Nov. 2011 - Singapore

14) Hatsune Miku Live Party, Mikupa - 8 Mar. 2012 - Tokyo, Japan

15) Miku no Hi Daikanshasai 39's Special Thanks Finale - 9 Mar. 2012 - Tokyo, Japan

There may be others, not including the various small Vocaloid Panels at various conventions and gatherings.