Note Frequency Chart (Hz)

How to use the note frequency chart

1. Tap a note. Every note in the chart is a button — tap one and the big readout shows its exact frequency in hertz, its MIDI number and its wavelength, and you'll hear a clean reference tone. The Play tone button replays the focused note.
2. Set your reference pitch. The whole chart is built around A4. Leave it at the concert standard of 440 Hz, or hit 432, 442 (common in orchestras) or 415 (Baroque) — every frequency recalculates instantly. Need something exact? Type any value from 400 to 466 Hz.
3. Highlight your instrument. Pick Guitar, Bass, Violin, Ukulele or the 88-key Piano range and the chart lights up the open-string or in-range notes so you can see the frequencies that actually matter to you.
4. Go the other way. Enter a frequency in the Reverse lookup box and the tool tells you the nearest note and exactly how many cents sharp or flat you are — handy when a tuner or a spectrum analyser hands you a raw number.
5. Save it. Copy the focused note, grab a share link that reopens at the same pitch and note, or download a printable PDF chart at your chosen A4.

Why this note frequency chart is different

Most "note frequency chart" pages are a single static table at A4 = 440 and nothing else. That's fine until you actually need to do something with the numbers. This tool is built for that:

• The reference pitch is yours to change. Move A4 to 432, 442 or 415 and every value updates. A static 440 table can't tell you that A4 = 432 makes middle C land at 256.87 Hz instead of 261.63 — this one does, live.
• You can hear it, not just read it. Each note plays a pure sine tone, so you can match a pitch by ear or check that a frequency sounds like what you expect.
• It works backwards. Type 445 Hz and it tells you that's an A4 nearly 20 cents sharp. No other note-frequency page does the reverse lookup, and it's the thing producers and anyone reading a tuner actually needs.
• It knows your instrument. Highlight guitar tuning and the six open-string frequencies jump out — the same numbers we use in guitar string notes explained and how to tune a guitar.
• Print or embed it. Download a clean PDF chart at your A4 or drop the interactive widget into a lesson page — free, with attribution built in.

How it works (the equal-temperament math)

Modern Western tuning splits the octave into twelve equal steps, so every semitone is the same ratio apart — the twelfth root of two, about 1.0595. Fix one note as a reference and every other note follows from it. The agreed reference is A above middle C (A4):

frequency(n) = A4 x 2^((n - 69) / 12)

   n  = MIDI note number   (A4 = 69,  middle C = C4 = 60)
   A4 = your reference pitch in Hz   (default 440)

   A4  (n=69)  ->  440 x 2^(0)      = 440.00 Hz
   C4  (n=60)  ->  440 x 2^(-9/12)  = 261.63 Hz
   A5  (n=81)  ->  440 x 2^(12/12)  = 880.00 Hz   (one octave up = double)

Reverse:  n = 69 + 12 x log2(freq / A4)
          cents off = 1200 x log2(freq / nearest-note-freq)

Two facts fall straight out of that formula. Going up one octave doubles the frequency (A4 440 → A5 880 → A6 1760). And changing your reference pitch scales the entire chart by the same ratio: pick A4 = 432 and every note is 432/440 = 98.18% of its 440 value. That's why the tool can redraw the whole thing the instant you touch the reference.

Worked examples

432 Hz vs 440 Hz

Set the reference to 440 and middle C reads 261.63 Hz. Switch to 432 and it drops to 256.87 Hz — about a third of a semitone lower. That's the whole "432 tuning" idea: not a different set of intervals, just the same equal-tempered scale anchored to a slightly lower A. Flip between the two presets and watch every row shift together.

The six guitar open strings

Highlight Guitar and the chart marks the standard tuning frequencies: E2 = 82.41 Hz, A2 = 110.00 Hz, D3 = 146.83 Hz, G3 = 196.00 Hz, B3 = 246.94 Hz and E4 = 329.63 Hz. Those are the exact targets a clip-on tuner is aiming for — the same ones behind our guitar tuner picks and the string tension calculator.

Reading a number off a tuner

Your tuner flashes 247 Hz and you're not sure what it is. Type it into the reverse lookup: B3, one cent sharp — you're basically in tune. Type 233 and it's A#3 (B♭3), a couple of cents flat. It turns a raw frequency into something you can act on.

Frequently asked questions

What is the frequency of each musical note?

In standard concert tuning (A4 = 440 Hz), the reference notes are A4 = 440 Hz, middle C (C4) = 261.63 Hz, and the lowest A on a piano (A0) = 27.50 Hz. Every other note comes from the formula freq = 440 × 2^((n − 69)/12). Use the chart above to read any note from C0 (16.35 Hz) to B8 (7902 Hz), and change the A4 reference to see how the numbers shift.

What is A4 = 432 Hz tuning?

432 Hz tuning simply anchors the scale to A4 = 432 instead of 440, lowering every note by the same small ratio (about 32 cents, roughly a third of a semitone). Some players prefer its slightly warmer feel; there's no change to the intervals themselves. Tap the 432 preset to see the full chart at that reference, or read more in how to tune a guitar.

How do I convert a frequency to a note?

Use the reverse lookup box: type the frequency in hertz and the tool returns the nearest equal-tempered note plus how many cents sharp or flat you are. Under the hood it's n = 69 + 12 × log₂(freq / A4), rounded to the nearest note, then the cents difference from that note's exact frequency.

Why doesn't my tuner match the chart exactly?

Two reasons. First, real instruments aren't perfectly equal-tempered — pianos are deliberately "stretch-tuned," and strings go slightly sharp when plucked hard. Second, your tuner may be calibrated to a different A4 (442 is common). Set the chart's reference to match your tuner and the numbers will line up. A handful of cents' difference is normal and often intentional.

What's the difference between frequency, MIDI number and note name?

They're three ways of naming the same pitch. The note name (like A4) is what musicians say; the MIDI number (A4 = 69) is what software uses; the frequency (440 Hz) is the physical vibration your ear hears. The chart shows all three at once so you can move between them.

Related tools

• Guitar String Tension Calculator — turn those open-string frequencies into pounds of tension for any gauge and tuning.
• 120 BPM Metronome — a drift-free practice click to play the pitches against.
• Guitar Scales Chart — every scale and mode mapped across the fretboard.
• Chord Transposer — move a progression to any key with correct spelling and capo shapes.
• Browse all free musician's tools by Julian →

Turning frequencies into a tuned instrument

This chart tells you the target; a good clip-on tuner is what actually gets your strings there, fast, even on a loud stage. The picks under the tool above change with what you're doing — the short version:

• Just want a dependable clip-on? The Snark SN5X is the one nearly everyone owns — quick, accurate, and it reads guitar, bass and violin straight off the headstock.
• Tuning to a set reference? The Fender FT-1 calibrates to A440 within a cent, so it matches this chart's default exactly.
• Working in 432 or an orchestral 442? The KLIQ UberTuner calibrates anywhere from 430–450 Hz, so it can hit an alternate reference precisely. See our full guitar tuner picks and, if you're building a first rig, the beginner acoustic and beginner electric guides.

Sources & methodology

• Frequencies use 12-tone equal temperament: f = A4 × 2^((n − 69)/12), with A4 = MIDI 69 and middle C = C4 = MIDI 60, per the standard scientific-pitch-notation and piano-key-frequency references.
• The default A4 = 440 Hz is the ISO 16 concert standard; 432, 442 and 415 Hz presets cover common alternate, orchestral and Baroque references.
• Wavelength uses a speed of sound of 343 m/s (dry air, 20 °C). Cents are 1200 × log₂(f / f_nearest).
• A fixture test checks the note-to-frequency values (A4, A0, C4, C8, guitar strings, and the 432/442 references), the note-name mapping and the reverse lookup on every build, so the tool can't drift from these known-correct numbers.

Equal-temperament values are exact for the chosen A4 reference; real instruments use stretched or just tuning, so a tuner may read a few cents off by design. Reviewed by Julian Reyes, MM (Berklee). About Julian · Last reviewed July 26, 2026.

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  &middot; Reviewed by Julian Reyes, MM (Berklee)
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