Free online chromatic tuner
Tune your instrument with your microphone: detect the musical note, read the pitch in hertz, and see exactly how many cents you are sharp or flat.
A note is not fixed the moment it starts. Its pitch can rise, sag, widen, or settle as the sound opens. Use the tuner to watch that movement and tune the sustained center, not only the first reading.
Get a musical reading
- Choose the microphone or active input.
- Play one clear, sustained note.
- Let the pitch settle before adjusting.
- Compare the cents deviation with what you hear.
- Tune for a stable center, not a flickering needle.
Stabilize pitch, cents, and intonation
Follow the life of the note
Watch the pitch after the attack: the real center often appears in the sustain, once timbre stops disguising the intonation.
Tune what the ear remembers
Use cents as a reference, then check whether the held center sounds calm, resonant, and true to the instrument.
Practical tuning checks
- Repeat softly after a hard attack; judge the sustain, not the first transient.
- Tune upward into the target when the mechanism has backlash, then recheck after the tension settles.
- On guitar or bass, compare the open string with the 12th fret; if they disagree, the instrument needs intonation work.
What the tuner actually measures
A · PitchA note name identifies a pitch class; the octave number identifies register. A3, A4, and A5 are three different A notes: 220 Hz, 440 Hz, and 880 Hz when A4 = 440 Hz.
Frequency is measured in hertz. An ideal 440 Hz signal repeats 440 times per second, while real instruments add attack noise, partials, room response, and changing tone color.
Cents, reference pitch, and display response
A · CentsOne cent is one hundredth of an equal-tempered semitone. Negative cents are flat, zero is aligned with the target, and positive cents are sharp.
Changing A4 from 440 Hz to 442 Hz changes the target frequencies. Display inertia changes the visual response only; it does not change the tuning reference.
Calculated references around A4 = 440 Hz
A · ListenThese values follow c = 1200 log2(measured frequency / target frequency). In twelve-tone equal temperament, the target is f(n) = A4 × 2^((n - 69) / 12), so changing A4 moves every target frequency while adjacent semitones keep the ratio 2^(1/12).
| Deviation | Frequency |
|---|---|
| -50 cents | 427.47 Hz |
| -25 cents | 433.69 Hz |
| 0 cents | 440.00 Hz |
| +25 cents | 446.35 Hz |
| +50 cents | 452.89 Hz |
Standard tuning references
E · InstrumentThese are practical references, not the only possible tunings. Low notes, microphone response, background noise, and strong overtones can still affect detection; low-G ukulele uses G3 instead of G4.
| Instrument | String | Note | Frequency |
|---|---|---|---|
| Guitar | 6 | E2 | 82.41 Hz |
| Guitar | 5 | A2 | 110.00 Hz |
| Guitar | 4 | D3 | 146.83 Hz |
| Guitar | 3 | G3 | 196.00 Hz |
| Guitar | 2 | B3 | 246.94 Hz |
| Guitar | 1 | E4 | 329.63 Hz |
| Four-string bass | 4 | E1 | 41.20 Hz |
| Four-string bass | 3 | A1 | 55.00 Hz |
| Four-string bass | 2 | D2 | 73.42 Hz |
| Four-string bass | 1 | G2 | 98.00 Hz |
| Ukulele high-G | G | G4 | 392.00 Hz |
| Ukulele high-G | C | C4 | 261.63 Hz |
| Ukulele high-G | E | E4 | 329.63 Hz |
| Ukulele high-G | A | A4 | 440.00 Hz |
| Violin | G | G3 | 196.00 Hz |
| Violin | D | D4 | 293.66 Hz |
| Violin | A | A4 | 440.00 Hz |
| Violin | E | E5 | 659.26 Hz |
| Viola | C | C3 | 130.81 Hz |
| Viola | G | G3 | 196.00 Hz |
| Viola | D | D4 | 293.66 Hz |
| Viola | A | A4 | 440.00 Hz |
| Cello | C | C2 | 65.41 Hz |
| Cello | G | G2 | 98.00 Hz |
| Cello | D | D3 | 146.83 Hz |
| Cello | A | A3 | 220.00 Hz |
Why microphone pitch readings move
G · SpectrumThe strongest spectral component is not always the fundamental. A microphone, room, or instrument body can emphasize an overtone and make octave errors more likely.
Vibrato changes pitch; tremolo changes amplitude. Both can make the meter move, but they are musically different.
Troubleshooting unstable readings
C · HelpMost tuner problems come from input level, room noise, attack transients, or partials that are stronger than the fundamental.
- If microphone access is blocked, open browser or site permissions and choose the intended input.
- If no note appears, increase the signal, reduce background noise, and let the note sustain.
- If the octave is wrong, play more gently and wait for the sustain; the tuner may be following an overtone.
- If open strings tune correctly but fretted notes sound wrong, check intonation, action, and string condition.
Temperament and musical intonation
D · IntervalsTwelve-tone equal temperament divides the octave into twelve equal ratios and supports modulation. Just intonation and Pythagorean tuning describe simple interval relationships, but the best pitch depends on harmonic context.
A pure perfect fifth at 3:2 is 701.955 cents; an equal-tempered fifth is 700 cents. A pure major third at 5:4 is 386.314 cents; an equal-tempered major third is 400 cents.