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MIDI Note Number Converter
Three-way converter between MIDI note numbers, note names, and frequencies in Hz. Full 128-note reference table (MIDI 0–127), GM Drum Map, velocity-to-dB chart, and audio playback for every note.
Three-Way Converter
MIDI
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
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.
- 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.
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.