A♯3 / B♭3 · 233.08 Hz

A♯3 is piano key 38 of 88 and MIDI note 58 - the low-mid register, around a male speaking and singing voice. Play the pure tone below, tune to it, or explore the note in every octave.

233.08Hz
Volume50%
Waveform

A♯3 at a glance

Frequency
233.08 Hz
Wavelength (in air)
1.47 m
MIDI note
58
Piano key
38 / 88
Octave
3
Enharmonic
B♭3

All values assume twelve-tone equal temperament at the international standard pitch of A4 = 440 Hz. In that system every semitone has the same size - a frequency ratio of 2^(1/12) - so A♯3 is exactly 440 × 2^(-11/12) Hz. Under alternative references the note shifts with the reference: at A4 = 432 Hz, A♯3 becomes 228.84 Hz.

A♯ in every octave

NoteFrequencyMIDIPiano key
A♯029.14 Hz222
A♯158.27 Hz3414
A♯2116.54 Hz4626
A♯3233.08 Hz5838
A♯4466.16 Hz7050
A♯5932.33 Hz8262
A♯61864.7 Hz9474
A♯73729.3 Hz10686

Each octave doubles the frequency - the simplest relationship in music, and the reason notes an octave apart sound like “the same note, higher”.

Neighboring notes

One semitone down is A3 at 220.00 Hz; one semitone up is B3 at 246.94 Hz. Need a frequency between notes, or a different waveform? The tone generator plays anything from 20 Hz to 20 kHz; the note ↔ frequency converter does the math both directions, and the chromatic tuner listens to your instrument and shows the offset in cents.

A♯3 FAQ

What frequency is A♯3?

A♯3 / B♭3 is 233.08 Hz in twelve-tone equal temperament with the standard reference of A4 = 440 Hz. Every semitone step multiplies the frequency by the twelfth root of two (about 1.0595), and A♯3 sits 11 semitones below A4.

What MIDI number and piano key is A♯3?

A♯3 is MIDI note 58 and key 38 of 88 on a standard piano. Octave numbering follows scientific pitch notation, where middle C is C4 (MIDI 60).

How do I tune to A♯3?

Play the tone above and match your instrument by ear until the beating between the two pitches slows and disappears, or use the chromatic tuner with your microphone for a cents readout. Small mistunings show up as slow beats: one beat per second at this pitch means you are about 7.4 cents off.