Play the eerie, gliding sound of a theremin right in your browser. Move across the pad to change pitch and up or down to change volume, or turn on webcam control and play by waving your hand in the air. Add vibrato, snap to a musical scale and give it echo and reverb.
Last updated:
Note–
Pitch–
Volume–
Press and drag here to play ← lower pitch · higher pitch → ↑ louder · quieter ↓
Tip: with a mouse, turn on "Play on hover" to glide without holding the button, like a real theremin.
Webcam control follows movement: wave one hand in front of the camera against a still background. The video is analysed in your browser and never recorded or uploaded.
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How to use the Online Theremin
Press and drag on the dark pad. Move right for a higher pitch and up for a louder sound; release to stop.
Shape the sound with the waveform, vibrato and glide controls. The classic tone with gentle vibrato sounds closest to a real theremin.
Turn on scale snap if you want every position to land on a note of a scale, which makes melodies much easier.
Try webcam control: allow the camera and wave one hand in front of it against a still background.
Press Record clip, play, then press Stop and download to save your performance.
How the pad maps to pitch and volume
Pitch changes evenly in musical steps across the pad: every note takes the same width, just as on a piano keyboard, so moving one twelfth of an octave to the right always raises the pitch by one semitone. The frequency is calculated with the equal-temperament formula f = 440 × 2(n − 69) / 12, where n is the MIDI note number and 69 is A4. Volume follows the square of the height above the bottom edge, which matches how loudness is perceived better than a straight line.
Range setting
Lowest note
Highest note
Frequency span
Good for
C3 – C5
C3, 130.8 Hz
C5, 523.3 Hz
2 octaves
Beginners, playing tunes accurately
C3 – C6
C3, 130.8 Hz
C6, 1046.5 Hz
3 octaves
General playing (default)
C2 – C6
C2, 65.4 Hz
C6, 1046.5 Hz
4 octaves
Big sci-fi swoops and sirens
C4 – C6
C4, 261.6 Hz
C6, 1046.5 Hz
2 octaves
Singing, soprano-like melodies
Scales for scale snap
Scale
Steps from the key note (semitones)
Notes in C
Character
Major
0, 2, 4, 5, 7, 9, 11
C D E F G A B
Bright, familiar melodies
Natural minor
0, 2, 3, 5, 7, 8, 10
C D E♭ F G A♭ B♭
Dark, mysterious
Major pentatonic
0, 2, 4, 7, 9
C D E G A
Nothing sounds wrong: easiest to improvise
Minor pentatonic
0, 3, 5, 7, 10
C E♭ F G B♭
Rock and folk riffs
Blues
0, 3, 5, 6, 7, 10
C E♭ F G♭ G B♭
Bluesy bends with the "blue" note
Tips for a convincing theremin sound
Use vibrato like a singer. Real thereminists shake the pitch hand slightly; a depth of 15–30 cents at 5–6 Hz sounds natural, while wide, fast vibrato sounds like a 1950s flying saucer.
Slide into notes. Start a little below the target pitch and glide up, and swell the volume in from the bottom of the pad instead of starting loud.
Keep the room in mind. A touch of reverb (20–40%) adds the spacious concert-hall feel; long delays create spooky echoes for Halloween effects.
For webcam play, sit with even lighting, keep your body still and move only one hand. A plain wall behind you gives the steadiest tracking.
A theremin is an electronic instrument invented by Leon Theremin around 1920 and played without touching it. One antenna controls pitch and the other controls volume as the player moves their hands near them. Its wavering, voice-like sound is famous from science-fiction film scores.
How do I play this online theremin?
Press and drag on the pad. The horizontal position sets the pitch (left is low, right is high) and the vertical position sets the volume (top is loud, bottom is quiet). On a computer you can also tick Play on hover to play just by moving the mouse, or use the arrow keys and hold Space.
How does the webcam control work?
The tool compares each video frame with the previous one and finds where movement happens. The center of that movement becomes your pitch and volume, so a waving hand works best against a still background. The video stays on your device and is never recorded or uploaded.
Why is it hard to play in tune?
A real theremin has no keys or frets, so the player must find each note by ear, and this tool behaves the same way when scale snap is off. Turn on scale snap to lock to the notes of a chosen scale, use the note lines as a guide, and pick a smaller range so notes are farther apart.
What does the glide setting do?
Glide (portamento) is how long the pitch takes to slide to a new position. Short glide gives quick, precise note changes; long glide makes the swooping slides typical of theremin playing, which sound especially nice combined with scale snap.
Is there a delay between my movement and the sound?
Browsers add a small audio delay, usually 10 to 40 milliseconds, depending on your device and audio output. Wireless headphones add much more, often 150 milliseconds or more, so wired headphones or speakers feel more responsive.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.