Open D tuner

Tune to Open D (D A D F# A D) with your phone or computer microphone. Press start, play a string and follow the needle.

Quick answer

Open D, low to high: D A D F# A D.

Mic off
E
Tap start, then play any string

  1. Click Start tuner and choose Allow when the browser asks for the microphone.
  2. Hold the guitar close to your laptop. The mic is usually next to the camera above the screen.
  3. Play one string and let it ring. Follow the needle to the middle.

Allow the microphone, then play one string close to your phone.

Sound stays on your device. Nothing is recorded or uploaded.

Instrument

Strings, low to high

Tap a string to hear its note. While the tuner listens, tap one to lock onto it.

Reference pitch A4 = 440 Hz

Leave this at 440 unless you are matching a piano or a record that is off standard pitch.

Open D: notes and frequencies

Open D: notes and frequencies with A4 = 440 Hz
StringNoteFrequency
6D273.42 Hz
5A2110.00 Hz
4D3146.83 Hz
3F#3185.00 Hz
2A3220.00 Hz
1D4293.66 Hz

Open D is D A D F# A D, from the lowest string to the highest. Strumming the open strings plays a D major chord. Common for slide, blues and fingerstyle folk.

How to tune

  1. Press Start tuner and allow the microphone.
  2. Play one string at a time and let it ring.
  3. Tune up if the needle sits left of center and down if it sits right. The note turns green within 3 cents.

Other tuners

Half step down tunerD standard tunerDrop D tunerDrop C tunerDrop B tunerOpen G tunerOpen D tunerOpen E tunerDADGAD tuner7-string guitar tuner7-string drop A tuner8-string guitar tuner8-string drop E tunerBass tuner5-string bass tunerUkulele tuner

Tuners for every setup

A clip-on works anywhere. A pedal tuner mutes your signal on stage.

As an Amazon Associate GuitarMath earns from qualifying purchases. How we choose gear.

Last updated November 14, 2026.