D4
293.665Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
62
Piano key
42
Octave
4
Frequency
293.665 Hz
Period
3.4052 ms
Wavelength
1.168 m
Pitch class
D
Notation
SPN
MIDI is the note number synths and software pass around (0–127). Pitch class is the note without its octave — all the Ds share one.
At other reference pitches
| Reference (A4) | D4 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 288.325 Hz | the alternative-tuning circle |
| 440 Hzstandard | 293.665 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 295 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 295.667 Hz | some sharper continental orchestras |
Every row is D4 — only the A4 you tune to changes. A frequency scales straight with the reference: D4 at 432 Hz is the 440 Hz value times 432⁄440.
Move around
Every D
Chords with D in them
D appears in each of these — see the whole chord grid.