string 1 · fret 21
C#6
1108.73 Hz
Guitar string 1, fret 21 — C#6
String 1 at fret 21 gives C#6 at 1108.73 Hz. On a 648 mm scale it sits 455.3 mm from the nut.
- Note
- C#6
- Frequency
- 1108.73 Hz
- MIDI number
- 85
- From the nut · 648 mm (Fender)
- 455.3 mm
- From the nut · 628 mm (Gibson)
- 441.3 mm
- From the nut · 650 mm (classical)
- 456.8 mm
- Ringing length
- 192.7 mm
The frets crowd as you climb
Frets are spaced by ratio, not by equal steps: each one divides the remaining length by the twelfth root of two. That is why the 12th fret lands at exactly half the string — the octave.
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String 1 is the thinnest. The string printed at the top is the one that sounds highest.
How to read this
- One fret is one semitone; twelve of them make an octave.
- Frequency multiplies by the twelfth root of two per semitone — A4 is 440 Hz.
- Fret position = scale length × (1 − 1 ÷ 2^(fret/12)).
- String 1 is the thinnest; standard tuning reads E-B-G-D-A-E from there.
Frequently asked questions
Q. What note is string 1, fret 21?
C#6, at 1108.73 Hz — MIDI number 85.
Q. Can I play the same note on another string?
Not within this fretboard.
Q. How far is this fret from the nut?
455.3 mm on a 648 mm scale, 441.3 mm on a 628 mm one.
Q. Where is the octave above?
Off the end of this string — you would take it on another one.