G#3 note frequency calculator

G#3 is MIDI note 56, -13 semitones from A4. At the standard A4 = 440 Hz that puts it at 207.652 Hz.

Hz
cents
N
kg/m
Frequency
207.6523Hz
≈ Rounded G#3 frequency
Period
0.004 815 74 s
Wavelength in air
1.6518
Quarter wavelength
0.4129
One octave up
415.3047 Hz
One octave down
103.8262 Hz
Equal-tempered fifth above
311.1270 Hz
Just fifth above
311.4785 Hz
How flat the tempered fifth is
1.9550 cents
String length at that tension
0.3046
MIDI note number
56
Show the working
  1. Reference pitch for A4 = 440
  2. Detune = 0
  3. Speed of sound = 343
  4. String tension = 80
  5. String mass per metre = 0.005
  6. semitones = -13 = -13
  7. Frequency = 440 * 2^(-13/12) * 2^(0/1200) = 207.652
  8. Period = 207.652 > 0 ? 1/207.652 : 0 = 0.004 815 74
  9. Wavelength in air = 207.652 > 0 ? 343 / 207.652 : 0 = 1.6518
  10. Quarter wavelength = 1.6518 / 4 = 0.412 95
  11. One octave up = 207.652 * 2 = 415.305
  12. One octave down = 207.652 / 2 = 103.826
  13. Equal-tempered fifth above = 207.652 * 2^(7/12) = 311.127
  14. Just fifth above = 207.652 * 1.5 = 311.479
  15. How flat the tempered fifth is = 311.127 > 0 ? 1200 * log2(311.479/311.127) : 0 = 1.955
  16. String length at that tension = 207.652 > 0 ? sqrt(80 / 0.005) / (2 * 207.652) : 0 = 0.304 574
  17. MIDI note number = 56 = 56

Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.

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    The formula

    • f = 440 x 2^((n - 69)/12), with n the MIDI note number
    • one cent is 2^(1/1200), so a detune of c cents multiplies by 2^(c/1200)
    • string frequency = sqrt(tension / linear density) / (2 x length)

    Equal temperament divides the octave into twelve equal ratios of 2^(1/12), which is irrational. Every interval except the octave is therefore slightly out of tune against the simple whole-number ratios the ear prefers.

    The tempered fifth is about 1.955 cents flat of a just fifth, which is close enough that almost nobody notices.

    Concert pitch is not universal: many orchestras tune to 442 or 443 Hz, and baroque performance often uses 415.

    G#3 at different concert pitches

    A4 reference G#3 frequency
    415 Hz 195.854 Hz
    430 Hz 202.933 Hz
    432 Hz 203.877 Hz
    435 Hz 205.293 Hz
    440 Hz 207.652 Hz
    442 Hz 208.596 Hz
    443 Hz 209.068 Hz
    444 Hz 209.540 Hz

    Frequently asked

    What frequency is G#3?

    207.652 Hz in equal temperament with A4 at 440 Hz.

    How is the frequency of a note calculated?

    Multiply the reference pitch by two raised to the number of semitones divided by twelve.

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