Guitar Tuner

Guitar Tuner is a tuning app for guitar, bass and ukulele. Pluck a string and it listens through your phone's microphone, works out which note you played, and shows you in real time how sharp or flat it is until the string is in tune. You do not need any extra equipment; the microphone is all it uses.

■ Just play
Pluck a string and the app finds which one it is. When the note is right, the display locks and a short buzz tells you so, which means you don't have to stare at the screen to know. You can also pick a string yourself and stay on it.

■ Read the fine detail
See the note name, the frequency, and exactly how far off you are in cents. The ruler spans 50 cents either way. Bring the marker to the middle and you're done. Anything within 5 cents counts as in tune.

■ Hear the reference
Press and hold a string to play its reference tone, so you can check by ear before you turn the peg.

■ Instruments and tunings
Guitar, 4 string bass, 5 string bass and ukulele.
Built in presets: Standard (EADGBE), Drop D, Half step down, Open G, Open D, DADGAD, Ukulele (GCEA), Bass (EADG), 5 string bass (BEADG).

■ Custom tunings
Set your own strings and notes, then save the tuning. If you live in an altered tuning, you never have to dial it in again.

■ Reference pitch
Adjust A4 from 435Hz to 445Hz. The default is 440Hz. Handy when you're matching another instrument or playing with an ensemble.

■ Daily tuning reminder
Get a nudge at a time you choose. Strings drift after a single day.

■ Light and dark themes
Follow the system setting or pick the look yourself.

■ Your audio stays on your phone
What the microphone hears is analysed on the device, only to work out the pitch. Nothing is recorded, stored or sent anywhere.