Online Guitar Tuner
Free online guitar tuner. Play reference tones for standard, Drop D, half-step-down, Open G, and DADGAD tunings, or detect pitch live from your microphone.
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What is Online Guitar Tuner?
The Online Guitar Tuner tunes your guitar two ways. Reference Tone mode synthesizes each open string as a layered harmonic tone so you can tune by ear, while Microphone mode listens to your instrument and shows the detected note, frequency, and cents deviation on a live meter. Five tunings are built in - Standard, Drop D, Half Step Down, Open G, and DADGAD - and everything runs locally in your browser.
Key Benefits
- Start tuning in seconds on phone, tablet, or desktop with nothing to install
- Tune by ear with realistic plucked-string reference tones instead of thin beeps
- Tune visually with a cents meter, green in-tune zone, and tune-up or tune-down guidance
- Stay private and offline - microphone audio is processed on-device only
Common Use Cases
- •Daily practice warm-up before playing songs or rehearsing with a band
- •Switching quickly between Standard, Drop D, or DADGAD for different songs
- •Setting up a new guitar or re-stringing after a string breaks
- •Checking intonation or drift mid-session without reaching for a hardware tuner
How to Use the Online Guitar Tuner
- Pick a tuning: Choose Standard, Drop D, Half Step Down, Open G, or DADGAD from the tuning selector at the top.
- Choose a mode: Use Reference Tones to tune by ear, or Microphone Tuner to see your pitch measured automatically.
- Tune each string: In reference mode, tap a string button and match its tone by ear. In microphone mode, pluck a string and watch the cents meter until the needle sits in the green zone.
- Confirm and repeat: The indicator turns green when a string is within plus or minus 5 cents. Repeat for all six strings, then double-check each one once more.
Key Features
- Five built-in tunings: Standard (E A D G B E), Drop D, Half Step Down, Open G, and DADGAD.
- Reference tone mode with one button per string showing note name and target frequency in Hz.
- Microphone mode with autocorrelation pitch detection, live note readout, and a cents deviation meter.
- Green in-tune zone at plus or minus 5 cents with clear tune-up or tune-down guidance.
- Runs 100 percent in the browser via the Web Audio API - offline, private, and install-free.
Frequently Asked Questions
How accurate is the microphone tuner?
Pitch is detected with autocorrelation and refined by parabolic interpolation, which typically resolves within about 1 cent on a clean, sustained note. Background noise, quick plucks, or cheap built-in microphones can reduce accuracy, so pluck steadily and let the note ring.
What tunings are supported?
Standard (E A D G B E), Drop D, Half Step Down (Eb Standard), Open G, and DADGAD. Frequencies are based on A4 equals 440 Hz equal temperament.
Does my audio get uploaded anywhere?
No. The tuner uses the Web Audio API inside your browser. Microphone audio is analyzed locally and never sent to any server, so the page even keeps working offline once loaded.
The needle jumps between notes. What should I do?
Move closer to the microphone, mute other sound sources, and pluck the string gently with your finger instead of a pick. Letting the note ring for a second or two gives the detector a stable signal to lock onto.