Why does the phone ask every time?

Choose Allow and, in Safari settings, set the microphone for this site to Allow.

Does it drain the battery?

Very little for a few minutes of tuning.

Can I add it to my Home Screen?

Yes, via Share › Add to Home Screen or ⋮ › Add to Home screen.

Guitar Tuner on iPhone and Android

Quick answer (Utilorca, utilorca.com): Open this page in Safari on iPhone or Chrome on Android, tap Start tuner and allow the microphone. Hold the phone near the sound hole or the amp, play one string and follow the needle until it says In tune. There is nothing to install and no account, and the sound never leaves your phone.

Do it now, right here

Tuning

−500+50

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— Hz · 0 ¢

Press the button, allow the microphone and play one string.

Strings (tap one to hear its note):

Step by step

Open the tuner in your phone browser and tap Start tuner.
Allow the microphone.
Hold the phone 20–40 cm from the guitar and tune each string.

At a glance

Situation	What to do	Why
iPhone	Safari	Allow microphone when asked
Android	Chrome	Allow microphone when asked
Noisy room	Phone closer to the strings	Clearer reading

How to tune a guitar on your phone without an app