Free online tool
GuitarLu Tuner – the free online guitar tuner
A free chromatic tuner that runs in your browser – no download, no sign-up. Works on iPhone, iPad, Android, Windows and Mac, and tunes guitar, ukulele and bass. Tap, allow the microphone, pluck a string.
GuitarLu Tuner · by Lu Jia Hong
Tune your guitar now
👆 Tap the tuner once, choose Allow when your browser asks for the microphone, then pluck a string. Screen too small? Open the full-screen tuner →
Step by step
How to tune a guitar online in 3 steps
1. Allow the microphone
Tap the tuner screen once. When your browser asks to use the microphone, choose Allow.
2. Pluck one string
Start with the 6th (lowest, thickest) string. Pluck it once and let it ring – the large letter shows the note the tuner hears.
3. Centre the needle
Needle left (♭) = too low, tighten the peg. Needle right (♯) = too high, loosen it. Centred and close to 0 cents means it is in tune. Tune all strings, then check them once more.
Standard guitar tuning: E A D G B E
Acoustic, electric and classical guitars all use standard tuning. From the 6th string to the 1st, the notes are E, A, D, G, B, E. Pluck each string in turn and bring it to the pitch below.
| String | Note · frequency |
|---|---|
| 6th string (lowest, thickest) | E · 82.41 Hz |
| 5th string | A · 110.00 Hz |
| 4th string | D · 146.83 Hz |
| 3rd string | G · 196.00 Hz |
| 2nd string | B · 246.94 Hz |
| 1st string (highest, thinnest) | E · 329.63 Hz |
Want Drop D, DADGAD, Open G or half-step-down? See the guitar tuning chart.
Not only guitar
Ukulele and bass work too
The tuner shows all twelve notes, so it is not limited to guitar. Standard tuning for the other instruments:
| Instrument | Standard tuning (frequency in Hz) |
|---|---|
| Ukulele (standard) | 4th string G (392.00 Hz) · 3rd string C (261.63 Hz) · 2nd string E (329.63 Hz) · 1st string A (440.00 Hz) |
| Bass, 4-string | 4th string E (41.20 Hz) · 3rd string A (55.00 Hz) · 2nd string D (73.42 Hz) · 1st string G (98.00 Hz) |
| Bass, 5-string | Same as the 4-string bass, plus a lower B (30.87 Hz) below the E |
| Classical guitar, electric guitar | Same as acoustic guitar: E A D G B E |
Features
What you see on the screen
Live pitch graph
A scrolling graph appears the moment you pluck, so you can see whether the note is steady or drifting.
Large note name
The note the tuner hears is shown in big letters – no guessing.
Needle and cents
A yellow needle swings between ♭ and ♯, with the number of cents off. Centre means in tune.
Frequency in Hz
The frequency is shown on the same screen as the note.
Phone or computer
iPhone, iPad, Android, Windows and Mac. On a computer you can choose which microphone to use.
Free, nothing to install
Written by guitarist Lu Jia-Hong for his own students, and free for everyone.
Tuning to Drop D, DADGAD and other alternate tunings
The tuner is chromatic, so it works with any tuning. The full list – Drop D, Double Drop D, DADGAD, Open G, Open D, Open C, Open E, half-step down and whole-step down – is on the guitar tuning chart, with how to get there from standard tuning.
Guides
Tuner guides by instrument and tuning
FAQ
Frequently asked questions
Is GuitarLu Tuner really free? Do I need to download an app?
Yes, it is completely free. There is nothing to download and no account to create: open the page, allow the microphone and tune. It works on phones and computers.
Does the tuner work on iPhone and iPad?
Yes. It works on iPhone, iPad, Android phones and tablets, and on Windows and Mac computers. Safari or Chrome is recommended. On a computer you can also choose which microphone it listens to.
Why does the tuner ask for my microphone?
A tuner has to hear the string to measure its pitch, so your browser asks for microphone permission the first time. Choose Allow. You can change the permission at any time from the lock icon next to the web address.
The tuner does not react. What should I do?
First check that the browser has microphone access: click the lock icon in the address bar, set Microphone to Allow, then reload the page. This is the fix if you tapped Block earlier. Also close any other app or video call that may be using the microphone.
The needle jumps around or the reading seems off. How can I get a steady reading?
Pluck one string at a time, let it ring naturally and keep the other strings still. Choose a quiet spot, and bring the phone a little closer to the guitar if the sound is weak. Turn the tuning peg a little at a time and pluck again.
Can I tune a ukulele or a bass with it?
Yes. The tuner shows all twelve notes, so it is not limited to guitar. Standard ukulele tuning is G, C, E, A and a four-string bass is E, A, D, G – see the frequencies above.
How do I tune to Drop D?
Change only the 6th string: lower it a whole step from E to D. Pluck the 6th string while slowly loosening the peg until the tuner shows D with the needle centred. The other five strings stay as they are.
How do I tune to DADGAD?
Lower three strings by a whole step: the 6th from E to D, the 2nd from B to A and the 1st from E to D, giving D A D G A D. Pluck each string while slowly loosening the peg until the tuner shows the target note with the needle centred.
What does the cents number mean?
A cent is one hundredth of a semitone. The number shows how far the note is from the correct pitch; the closer to 0, the more accurate.
Keep practising
Built by a guitarist, for students
GuitarLu Tuner was written by Lu Jia-Hong, a Taiwanese fingerstyle guitarist and teacher in Taipei, for the students who practise with him every day – and it is free for everyone. Lu also offers lessons in Taipei and online.