Use one of the 30+ built-in alternate guitar tunings (Open, Dropped, Double Dropped, Minors, Fourths...) or create your own custom tuning.
Adjustable reference note frequency (A440), algorithm sensitivity and tolerance (in cents).
Automatic detection of tuned strings.
Click on the note name to hear the actual string sound. This way you can tune your guitar by ear, switch back to automatic mode and than check how good your ears are.
Various note naming schemes: English (CDEFGAB), German (CDEFGAH), Latin (DoReMiFa...)