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MIDI Note Number Converter

This free MIDI note converter maps note numbers, note names, and frequencies in Hz — three ways, instantly. Full 128-note reference table (MIDI 0–127), GM Drum Map, velocity-to-dB chart, and audio playback for every note. Whether you’re programming a DAW, building a synthesizer patch, or writing MIDI controller firmware, the equal-tempered pitch formula (f = 440 × 2^(n−69)/12) underlies every conversion here.

Three-Way Converter

MIDI Number (0–127)

MIDI

060127

Note Name

Frequency (Hz)

Hz

MIDI # 69

Note Name A4

Octave 4

Frequency 440.000 Hz

Period 2.2727 ms

Cents Deviation 0 cents

Interactive Piano (C4 – B5) — MIDI 60–83

Search / Filter Table

Complete 128-Note MIDI Reference (0–127)

MIDI #	Note	Octave	Frequency (Hz)	Period (ms)	Play	Select

Velocity-to-dB Reference

Dynamic	Symbol	Velocity	Approx. dB	Description

General MIDI Drum Map (MIDI 35–81)

MIDI #	Drum Name	MIDI #	Drum Name

How to Use This Converter

Enter a MIDI number — Type any value from 0 to 127 or use the slider. The converter instantly shows the corresponding note name, frequency in Hz, period in milliseconds, and cents deviation. Click “Play Note” to hear it.
Select a note name — Choose from the dropdown menu (C-1 through G9). The MIDI number and exact Hz frequency are displayed immediately. Use this when you know the musical note but need the MIDI number for your DAW or synthesizer. If you want to generate and hear a specific pitch directly, try the tone generator.
Enter a frequency in Hz — Type any frequency and the converter finds the nearest MIDI note, shows the note name, and calculates the cents deviation from the exact MIDI pitch. Perfect for identifying unknown frequencies or checking microphone/tuner readings. You can also use the piano note frequency finder to browse pitches visually on an 88-key layout.

How to Convert MIDI Note to Hz: Worked Example

The tool uses the equal-temperament pitch formula f = 440 × 2^{(n − 69) / 12}, where n is the MIDI note number and 69 is the anchor (A4 = 440 Hz). To convert MIDI to frequency for note 60 (middle C): f = 440 × 2^{(60 − 69) / 12} = 440 × 2^−0.75 = 440 × 0.5946 ≈ 261.63 Hz. Going the other direction, to convert a frequency to a MIDI note number use n = 69 + 12 × log₂(f / 440) — this is the note-to-MIDI-number formula underlying the Hz input field above.

Two useful reference values to memorize: MIDI 69 = A4 = 440 Hz (the international tuning standard) and MIDI 60 = C4 = 261.63 Hz (middle C). Every semitone step multiplies the frequency by the twelfth root of 2 (≈ 1.05946), so moving up 12 semitones (one octave) always doubles the frequency. The complete 128-note MIDI reference table above serves as a handy MIDI note chart covering the full range from C-1 to G9. For a full table of every semitone ratio across the audible range, see the equal temperament chart. To check how any pitch compares to these anchors by ear, use the chromatic tuner or explore semitone distances with the interval calculator.

Frequently Asked Questions

What is MIDI note 0?

MIDI note 0 is C-1 (C in octave negative one), with a frequency of approximately 8.176 Hz. This is far below the range of human hearing (~20 Hz) and below the lowest piano key. While MIDI notes 0-20 are rarely used for pitched instruments, they can serve as control signals or trigger sub-bass synthesizers.

What MIDI note number is middle C?

Middle C is MIDI note 60 (C4), with a frequency of approximately 261.63 Hz. This is the standard reference point for MIDI note numbering. Some older software uses C3 for middle C (MIDI 60), but the C4 convention (where MIDI 0 = C-1) is the most widely adopted standard today.

How do I convert a frequency to a MIDI note number?

Use the formula: MIDI = 69 + 12 × log2(f / 440). Enter any frequency in the Hz input field above and the converter will calculate the nearest MIDI note number and show the cents deviation. For example, 440 Hz = MIDI 69 (A4), 261.63 Hz = MIDI 60 (C4).

What is the GM Drum Map?

The General MIDI (GM) Drum Map assigns specific percussion instruments to MIDI notes 35-81 on Channel 10. For example, MIDI 36 is Bass Drum 1, MIDI 38 is Acoustic Snare, and MIDI 42 is Closed Hi-Hat. This standard ensures drum patterns sound correct across different GM-compatible synthesizers and software.

What is MIDI velocity and how does it relate to volume?

MIDI velocity is a value from 0 to 127 that represents how hard a note is struck. Velocity 0 is typically a note-off message, while 127 is maximum intensity. The mapping from velocity to actual volume (dB) varies by instrument, but a common approximation is: dB = 20 × log10(velocity / 127). Standard dynamic markings map roughly to: pp=40, mp=64, mf=80, f=100, ff=120.

Why does MIDI only go up to 127?

MIDI uses 7-bit data values, which gives a range of 0 to 127 (2^7 - 1 = 127). This applies to note numbers, velocity, and control change values. The 8th bit is reserved as a status bit to distinguish data bytes from command bytes in the MIDI protocol. This 128-value range was designed in 1983 and covers over 10 octaves, which exceeds the range of any acoustic instrument.

Why do different DAWs call middle C by different note names?

There is no universal agreement on octave numbering in MIDI software. Most modern DAWs (Ableton Live, Logic Pro, Cubase) follow the MIDI standard where MIDI 60 = C4. However, older software like certain Roland and Korg instruments label the same note as C3, shifting all octave numbers down by one. If a patch sounds an octave off from what you expect, check your DAW’s octave offset setting — the underlying MIDI note number (60) is always identical regardless of the displayed name.

What are cents deviation and why does it matter for tuning?

A cent is one hundredth of a semitone. When you enter a frequency that falls between two MIDI notes, the converter shows how many cents above or below the nearest MIDI pitch it sits. This matters for microtuning, alternate temperaments (just intonation, meantone), and for identifying whether a recorded or live instrument is sharp or flat. A deviation of ±50 cents means you are exactly halfway between two semitones. For precise tuning work, also see the equal temperament chart which shows every semitone ratio across the full audible range.

Which MIDI channel is used for drums, and why?

The General MIDI specification reserves Channel 10 exclusively for percussion. On Channel 10, note numbers do not represent pitched tones — they select drum sounds according to the GM Drum Map (MIDI 35–81). This is why sending a melody line to Channel 10 by mistake produces a drum pattern instead of the intended notes. The GM Drum Map table above lists all 47 standard percussion assignments so you can quickly look up which MIDI note triggers a kick, snare, hi-hat, or cymbal.

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