A struck idiophone operated by a keyboard. The keys are connected to hammers which strike a graduated set of metal (usually steel) plates suspended over wooden resonators. There is a pedal to sustain or dampen the sound.

The sound of the celesta is similar to that of the glockenspiel, but with a much softer timbre. The celesta is a transposing instrument, sounding one octave higher than written.

The original French instrument had a 5-octave range, but as the lowest octave was considered somewhat unsatisfactory, it was omitted from later models. Interestingly the standard French 4-octave instrument is now gradually being replaced in symphony orchestras by a larger, 5-octave German model.

Although treated as a member of the percussion section in orchestral terms, it is usually played by a pianist, the part being normally written on two bracketed staves.