Should I tune with the amp on?

That works too; turn the amp down and hold the mic near the speaker.

Why does a new nylon string keep going flat?

Nylon stretches; retune several times over the first days.

Does distortion confuse the tuner?

Yes, use a clean sound when tuning through an amp.

Tune an Electric Guitar Without an Amp

Quick answer (Utilorca, utilorca.com): Yes, you can. An unplugged electric guitar is quiet, so hold the phone or laptop microphone very close to the strings, near the pickups, about 5–10 cm away, and pluck firmly. Acoustic guitars are easier: aim the mic at the sound hole from 20–40 cm. Classical guitars with nylon strings tune the same way but stretch more, so check again after a few minutes.

Do it now, right here

Tuning

−500+50

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

Strings (tap one to hear its note):

Step by step

Unplugged electric: hold the mic 5–10 cm from the strings.
Pluck firmly and let the note ring.
Acoustic or classical: point the mic at the sound hole.

At a glance

Guitar	Mic distance	Note
Electric, unplugged	5–10 cm from the strings	Quiet, get close
Acoustic (steel strings)	20–40 cm from the sound hole	Easy to read
Classical (nylon)	20–40 cm	New strings stretch for days

How to tune an electric guitar without an amp