D (musical note)

D is a musical note a whole tone above C, and is known as Re within the fixed-Do solfege system. An enharmonic note is C, which is a diatonic semitone below D♯.

When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of middle D (D₄) is approximately 293.665 Hz. See pitch for a discussion of historical variations in frequency.

Designation by octave

Scientific designation	Helmholtz designation	Octave name	Frequency (Hz)
D-1	D͵͵͵ or ͵͵͵D	Subsubcontra	9.177
D0	D͵͵ or ͵͵D	Subcontra	18.354
D1	D͵ or ͵D	Contra	36.708
D2	D	Great	73.416
D3	d	Small	146.832
D4	d′	One-lined	293.665
D5	d′′	Two-lined	587.33
D6	d′′′	Three-lined	1174.659
D7	d′′′′	Four-lined	2349.318
D8	d′′′′′	Five-lined	4698.636
D9	d′′′′′′	Six-lined	9397.273

See also

• D major
• D minor