What Do Piano Foot Pedals Do?
Updated Nov 12, 2026 · By 
Jonah Mercer · Editorial policy
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A piano pedal changes how long a note sounds after you lift your finger from the key. The sustain pedal holds the note so it keeps sounding. An acoustic piano has a set of pedals for sustain, sostenuto and soft playing, while the products shown here are sustain pedals for keyboards and digital pianos.
What the sustain pedal does
Press the sustain pedal and the note you play keeps sounding after you lift your finger from the key. On an acoustic piano it works as the damper pedal, lifting the dampers from the strings so they ring on. On a keyboard or digital piano, the pedal sends the same hold signal to the instrument. Lift your foot and the sound stops as normal.
What the other pedals do
An acoustic piano has a set of pedals. The sostenuto pedal in the middle holds only the notes you are already holding down when you press it, while the notes you play after stay short. The soft pedal on the left makes the sound quieter by shifting the hammers. The products shown here are sustain pedals only, so they cover the right pedal.
How to plug a sustain pedal in
Plug the pedal into the sustain pedal socket on the back or side of your keyboard or digital piano. The RockJam and the RNSXYAT use a 6.35mm plug, and the Casio pedals use a 1/4 inch plug, which is the same size. Turn the keyboard on after you plug the pedal in, then press a key and the pedal to check that the note holds.
What to do if the pedal works backwards
If the note holds when your foot is off the pedal and stops when you press it, the pedal polarity is reversed. The RockJam and the RNSXYAT have a polarity switch on the side, so flip the switch and check the pedal again. Press a key with the pedal up and with the pedal down to confirm the note holds only when you press the pedal.
How to keep the pedal in place
A sustain pedal can slide on a hard floor as you play. The RockJam has an anti-slip rubber bottom, and the RNSXYAT has a non-slip rubber bottom that grips the floor. Place the pedal where your foot rests without stretching, and check that it stays put before you start playing.
What you need
RockJam 6.35mm Sustain Pedal for Electronic Keyboards
A sustain pedal with a polarity switch, an anti-slip rubber bottom and a 6.35mm plug for keyboards and digital pianos.
- Polarity switch
- 2-year warranty stated
RNSXYAT Sustain Pedal
A sustain pedal with a polarity switch, a non-slip rubber bottom and a 1/4 inch plug, made from alloy and plastic.
- Polarity switch
Casio SP3 Sustain Pedal for Keyboards Standard
A piano-style sustain pedal for Casio keyboards and digital pianos with pedal jacks, with a 1/4 inch plug.
- Piano-style pedal
Casio SP-20
A piano-style sustain pedal that sustains notes in the same way as the damper pedal on an acoustic piano.
- Piano-style pedal
These come from our ranked list Best Sustain Pedal for Piano, which compares them spec by spec.
Frequently asked questions
Do I need a pedal for a digital piano?
No, a digital piano plays without a pedal, but a sustain pedal holds notes after you lift your fingers from the keys. The products shown here are sustain pedals for keyboards and digital pianos with a pedal socket. Plug the pedal in and the hold works from the pedal instead of the keys.
Will a sustain pedal fit my keyboard?
Check the pedal socket on your keyboard. The RockJam lists a 6.35mm sustain pedal socket, and the Casio SP3 lists a 1/4 inch sustain pedal input. The RNSXYAT lists a 1/4 inch plug, so match the plug to the socket on your keyboard.
Why does my pedal sustain when I am not pressing it?
The pedal polarity is reversed, so the keyboard reads the pedal as pressed when your foot is off it. Flip the polarity switch on the side of the pedal. The RockJam and the RNSXYAT have a polarity switch, so check the pedal again after you flip it.
What is the difference between a sustain pedal and a damper pedal?
On an acoustic piano they are the same pedal: the sustain pedal is the damper pedal, and it lifts the dampers from the strings. The Casio SP-20 is designed to sustain notes in the same way as the damper pedal on an acoustic piano. On a keyboard the pedal sends the hold signal instead.
Ranked sustain pedals lists
More how-to guides
Product details come from each Amazon listing and can change. Check the listing before you buy.