Circle Of Fifths App is a lightweight iPhone application centered around the fundamental concept of the circle of fifths in music theory. This tool illustrates the relationship among the 12 tones of the chromatic scale, their respective key signatures, and the major and minor keys associated with them. At the starting point of the circle lies C major, characterized by having no sharps or flats in its key signature. Moving clockwise around the circle reveals keys with progressively more sharps, while counterclockwise showcases keys with increasing flats.

The app provides a visual representation of the circle of fifths, making it a handy reference for musicians, composers, and music enthusiasts looking to understand key relationships and harmonic structure more intuitively.