Fretnook / Free tools / Scale Finder & Ear Trainer
Open to everyone · no sign-up

Guitar scale finder & ear trainer

Not sure what key you are jamming in? Play a few notes and Fretnook listens through your microphone, ranks the scales that fit, and lights up the fretboard so you can see where they live. Strum a chord and it will name that too.

Open to everyone — no sign-up. Audio is analysed in your browser and is never uploaded.
Quick start

Find your scale in four steps

  1. Press Listen

    Almost everything in Fretnook needs live microphone input. Press Listen in the top-right corner and allow the browser's microphone prompt. An audio interface or USB microphone works too.

  2. Pick a mode

    Use the switch at the top of the Ear Trainer: Auto-detect to discover the scale you are playing, Target scale to practise a scale you choose, or Chord ID to name a chord you strum.

  3. Play

    In Auto-detect just play a riff or noodle for a few seconds. In Target scale, pick a root and scale first. In Chord ID, strum all six strings and let the chord ring.

  4. Read the wheel and the fretboard

    The wheel shows the current note, its frequency and how sharp or flat it is. The fretboard diagram lights up every root and scale tone across frets 0 to 12 and marks the note you are playing right now.

What you get

Three ways to train your ear

Auto-detect

Ranks the scales that best fit your recent notes and shows the top few candidates, because several scales can share the same notes.

Target scale

Choose a root and a scale. A badge tells you whether the note you are playing is in the scale or not, so wrong notes stand out immediately.

Chord ID

Reads the harmonic content across all six strings at once and names the chord you strummed.

Fretboard map

Every occurrence of the root and scale tones across frets 0 to 12, so you see where a scale's shape sits on the neck.

Six tunings

Standard, Drop D, Whole Step Down, Open G, Open D and Open E. The fretboard, string names and tuner targets all follow your choice.

Note history

A strip under the wheel shows your last few notes, handy for spotting what you just played.

Why auto-detect shows several scales, not just one

A major scale and its relative minor use exactly the same seven notes: C major and A minor share every note, for example. Pentatonic scales overlap in a similar way. A tool that names a single answer from a short phrase is guessing.

Fretnook shows a ranked short list instead, ordered by how well your recent notes fit each scale. As you play more notes, and especially notes that emphasise the root or the third, the right answer rises to the top. Treat the list as a strong hint and let your ear decide between close neighbours.

Practise with a target scale

Target scale mode is built for learning shapes. Choose the root and scale you are working on, such as A minor pentatonic or G major, and play. The badge turns on when the note you are playing belongs to the scale, and the fretboard shows where all the scale tones sit so you can connect the sound with the position.

Because the fretboard follows your selected tuning, it works the same way in Drop D, Whole Step Down or an open tuning. You can also send a key from a recorded song straight into the Ear Trainer from the Songs tool, so the neck lights up with the notes to solo with.

Getting a good chord reading

Chord ID works best on a full strum that is allowed to ring. Playing a single note or muting the strings quickly gives it little to work with. Strum all six strings, leave the chord ringing for a second or two, and keep the microphone close to the guitar in a quiet room.

Questions

Frequently asked questions

Is the scale finder free?
Yes. The Ear Trainer and the Tuner are open to everyone with no account or payment.
Does it work with an electric guitar?
It listens through a microphone or an audio interface. That means an acoustic guitar in front of a microphone, an amp with a microphone, or an electric guitar plugged into a USB interface all work. See the gear page for setup.
How does it know which scale I am in?
It tracks the notes you play and ranks common scales by how well they fit. It is an estimate, and it improves as you play more notes.
Can it tell me the chords in a song?
Chord ID is for chords you play into the microphone. To see the chords in a recorded song, load the file in the Songs tool, which analyses key, tuning and chords.
Which scales does it know?
Major, minor, the pentatonic scales, blues and other common scales. Pick the root and scale from the menus in Target scale mode.
More free tools

Keep going in the same rack

See your scale light up the fretboard.

Fretnook is free and runs in your browser. Your microphone audio and recordings stay on your device.

● Open the Ear Trainer