What is a Perfect Fourth?

A perfect fourth is a musical interval that represents the distance between two notes that are five semitones apart. In Western music theory, this interval occurs when the second note is four letter names higher than the first. For example, the distance between the notes C and F forms a perfect fourth.

The perfect fourth has a strong and stable sound and is considered a consonant interval in most musical contexts. It is commonly used in melodies and harmonies and often appears in chord structures and scale patterns. Because of its balanced sound, the interval can function well both melodically and harmonically in many musical settings.

Perfect fourths appear frequently in many musical styles, including classical, rock, jazz, and folk music. They are also commonly used in guitar playing because many adjacent strings are tuned a perfect fourth apart. This interval plays an important role in shaping chord voicings, harmonic progressions, and melodic movement across many genres of music.