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Musical note · Octave 2

B2

B2 = 123.47 Hz. Play the note, see it in other tunings, find it on piano and guitar, and explore its intervals.

123.47Hz

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123.47 HzFrequency at A4 = 440 Hz
47MIDI note number
27Piano key (of 88)
2.78 mWavelength in air

About B2

B2 has a frequency of 123.47 Hz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 47 and key number 27 on an 88-key piano.

In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so B2 is 22 semitones below A4: f = 440 × 2^((47 − 69) / 12) = 123.47 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.

B2 frequency in different tunings

Tuning referenceB2 frequency
A4 = 440 Hz (ISO 16 standard)123.47 Hz
A4 = 442 Hz (many European orchestras)124.03 Hz
A4 = 443 Hz (Berlin, Vienna)124.31 Hz
A4 = 435 Hz (French diapason normal, 1859)122.07 Hz
A4 = 432 Hz (alternative tuning)121.23 Hz
A4 = 415 Hz (Baroque pitch)116.46 Hz
C4 = 256 Hz (scientific pitch)120.82 Hz

Where to play B2 on a guitar

Standard tuning (E A D G B E), frets 0–22.

  • 6th string (low E), fret 7
  • 5th string (A), fret 2

Intervals from B2

IntervalNoteFrequencyRatio (just)
Minor secondC3130.81 Hz16:15
Major secondC♯3138.59 Hz9:8
Minor thirdD3146.83 Hz6:5
Major thirdD♯3155.56 Hz5:4
Perfect fourthE3164.81 Hz4:3
TritoneF3174.61 Hz45:32
Perfect fifthF♯3185 Hz3:2
Minor sixthG3196 Hz8:5
Major sixthG♯3207.65 Hz5:3
Minor seventhA3220 Hz9:5
Major seventhA♯3233.08 Hz15:8
OctaveB3246.94 Hz2:1

Instruments and voices that can play B2

Frequently asked questions

What is the frequency of B2?

B2 is 123.47 Hz when A4 = 440 Hz (121.23 Hz if A4 = 432 Hz).

What MIDI number is B2?

B2 is MIDI note number 47.

Is B2 on a piano?

Yes – it is key 27 of 88.

Where is B2 on the guitar?

In standard tuning: 6th string (low E), fret 7; 5th string (A), fret 2.