Frequency Counter Music

Notes counted —

Distinct pitches: —
Pitch classes used: —
Most frequent note: —
Lowest note: —
Highest note: —
Range (semitones): —

Paste notes in scientific pitch notation and the counter tallies each pitch, merges enharmonic spellings like F#3 and Gb3, and shows the frequency of every note. With A4 at 440 Hz, the line C4 E4 G4 C4 gives four notes, C4 twice at 261.63 Hz, and a range of 7 semitones.

About this tool

Analysing a melody, a bass line or an exercise often starts with a simple question: which notes does it use, and how often? This counter reads a list of note names, counts each pitch, and lists them from most to least used with their share of the total and their frequency in hertz. It also reports the lowest and highest notes and the range between them in semitones, which helps when checking whether a part fits a singer or an instrument. You can pick A4 = 440 Hz, the concert standard, or 432 or 442 Hz used by some orchestras and tuners. Frequencies follow twelve-tone equal temperament, so it does not model just intonation or historical tunings, and it does not read audio or MIDI files.

How to use it

Enter the notes
Type or paste notes like C4 Eb4 G#3, separated by spaces, commas or new lines, or open a .txt file.
Choose the tuning reference
Pick A4 = 440, 432 or 442 Hz; every frequency in the table follows that choice.
Read the counts
See total notes, distinct pitches, the most frequent note, the lowest and highest notes and the range.
Check the table
Each pitch is listed with its count, share of all notes and frequency in Hz.

Examples

A C major arpeggio

Notes: C4 E4 G4 C4
Tuning reference (A4): A4 = 440 Hz

Result Notes counted: 4
Distinct pitches: 3
Pitch classes used: 3
Most frequent note: C4 (2×)
Lowest note: C4 – 261.63 Hz
Highest note: G4 – 392 Hz
Range (semitones): 7

Each note becomes a MIDI number: n = 12 × (octave + 1) + semitone, so C4 = 60 and A4 = 69.
Frequency f = 440 × 2^((n − 69) ÷ 12). For C4: 440 × 2^((60 − 69) ÷ 12) = 261.63 Hz.
Range = 67 − 60 = 7 semitones.

Middle C appears twice, so it tops the count; the span from C4 up to G4 is a perfect fifth of 7 semitones.

A in 432 Hz tuning

Notes: A4, A3, A4
Tuning reference (A4): A4 = 432 Hz

Result Notes counted: 3
Distinct pitches: 2
Pitch classes used: 1
Most frequent note: A4 (2×)
Lowest note: A3 – 216 Hz
Highest note: A4 – 432 Hz
Range (semitones): 12

Each note becomes a MIDI number: n = 12 × (octave + 1) + semitone, so C4 = 60 and A4 = 69.
Frequency f = 432 × 2^((n − 69) ÷ 12). For A4: 432 × 2^((69 − 69) ÷ 12) = 432 Hz.
Range = 69 − 57 = 12 semitones.

With A4 set to 432 Hz the A an octave below sits at exactly half, 216 Hz, and both count as one pitch class.

Sharps, flats and a stray word

Notes: F#3 Gb3 hello Bb2
Tuning reference (A4): A4 = 440 Hz

Result Notes counted: 3
Distinct pitches: 2
Pitch classes used: 2
Most frequent note: F#3 (2×)
Lowest note: A#2 – 116.54 Hz
Highest note: F#3 – 185 Hz
Range (semitones): 8

Each note becomes a MIDI number: n = 12 × (octave + 1) + semitone, so C4 = 60 and A4 = 69.
Frequency f = 440 × 2^((n − 69) ÷ 12). For F#3: 440 × 2^((54 − 69) ÷ 12) = 185 Hz.
Range = 54 − 46 = 8 semitones.

F#3 and Gb3 are the same key on a piano, so they are counted together; the word hello is skipped with a warning.

How it is calculated

n = 12 × (octave + 1) + semitone; f = A4 × 2^((n − 69) ÷ 12)

n: MIDI note number, where C4 is 60 and A4 is 69
semitone: position of the letter in the octave (C = 0 … B = 11), plus 1 per sharp and minus 1 per flat
A4: the chosen reference pitch in Hz
f: frequency of the note in hertz

Every note is turned into a MIDI number so that enharmonic spellings such as C#4 and Db4 land on the same value and are counted together. In equal temperament each semitone multiplies the frequency by the twelfth root of two, so a note 12 semitones above A4 is exactly double. The range is the highest MIDI number minus the lowest.

When not to use it

To find the pitch of a recording, use a tuner or spectrum analyser; this tool reads note names, not audio.
For music in just intonation, Pythagorean or other historical tunings, the equal-tempered frequencies here will differ by a few cents.

Common mistakes

Leaving off the octave number, so a bare C or F# is skipped rather than counted.
Assuming middle C is C3; in scientific pitch notation used here it is C4, about 261.63 Hz.
Writing solfège syllables like do or re, which the counter does not read.

Frequently asked questions

What is the frequency of middle C?

With A4 tuned to 440 Hz, middle C (C4) is 261.63 Hz. It sits nine semitones below A4, so its frequency is 440 × 2^(−9/12). At A4 = 432 Hz it drops to about 256.87 Hz.

Are C#4 and Db4 counted as the same note?

Yes. They are the same piano key and the same frequency in equal temperament, so the counter merges them and shows the sharp spelling in the table.

How should I write flats and sharps?

Use # or ♯ for sharp and b or ♭ for flat after the letter, then the octave: F#3, Bb2, E♭5. A double sharp can be written x, and a double flat bb.

What does pitch classes used mean?

A pitch class ignores the octave, so A3, A4 and A5 all count as one class. A melody using all twelve pitch classes is fully chromatic; a C major scale uses seven.

Why offer 432 and 442 Hz?

440 Hz is the ISO 16 concert pitch. Many European orchestras tune slightly higher, around 442 Hz, and some musicians prefer 432 Hz. Changing the reference shifts every frequency by the same ratio but leaves the counts unchanged.

What happens to text that is not a note?

Anything that does not match a letter, an optional accidental and an octave number is skipped, and a warning lists the first few skipped items so you can correct them.

Cite this tool

Using this tool in an assignment, article or report? Copy a citation, or a link for your website.

APA

Tools Directory Editorial Team. (2026, October 12). Frequency Counter Music. Tools Directory. Retrieved October 27, 2026, from https://tools.milunir.com/video-audio/music-and-audio-theory/frequency-counter-music/

MLA

Tools Directory Editorial Team. “Frequency Counter Music.” Tools Directory, 12 Oct. 2026, https://tools.milunir.com/video-audio/music-and-audio-theory/frequency-counter-music/. Accessed 27 Oct. 2026.

Chicago

Tools Directory Editorial Team. “Frequency Counter Music.” Tools Directory. Last modified October 12, 2026. Accessed October 27, 2026. https://tools.milunir.com/video-audio/music-and-audio-theory/frequency-counter-music/.

Link

<a href="https://tools.milunir.com/video-audio/music-and-audio-theory/frequency-counter-music/">Frequency Counter Music – Tools Directory</a>