This tuner for guitar, mandolin, ukulele, fiddle, banjo, bass guitar allows standard and open* tunings.
The program shows the name of the note, together with its place on the stave, and numerical values of pitch/frequency. If the open tunings doesn't fit your needs, you can use the keyboard (in chromatic mode) and choose any other note to tune your instrument.
[*] The open-tunings available are:
Guitar: Standard (E-A-D-G-B-E), Standard + 1/2 tone, Standard - 1/2 tone, Standard - 1 tone, Standard - 2.5 tone, Standard - 3.5 tone, Standard + D bass, Lute, Lute (2), Open C, Open C Minor, C Maj6, C Maj79, C 6Add9, C 6/9/11#, Open D, Open D Minor, D Sus2, D Sus4, D Maj6, Dsus4/6, Dsus4/6 (2), D7 Tuning, D Maj7, Open E, Open E Minor, Open F, Open F Minor, Open G, Open G Minor, G Maj6, Open A, Open A Minor, Open B, Open B Minor, Perfect 4th, Dobro (Std).
Mandolin: Standard, Low, Alto, Mandola, Open C, Open D, Open E, Open G, Open A, Dropped D, Italian, French.