Full-Size Keys on MIDI Controllers
Updated Nov 13, 2026 · By 
Jonah Mercer · Editorial policy
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Full-size keys on a MIDI controller are keys at the same width as piano keys, so spacing stays the same when moving between the controller and a piano. The M-AUDIO Keystation 49 MK3 has 49 full-size keys, while the Akai MPK Mini models have 25 and 37 mini keys, which trade key width for a smaller footprint.
What full-size keys mean
A full-size key matches the width of a piano key. On a controller, that width lets a player use the same hand spacing as on a piano, with 88 keys on a full piano as the reference. Mini keys are narrower, so the same number of keys fits a shorter board. A 49-key controller with full-size keys takes more desk width than a 25-key controller with mini keys, and the M-AUDIO Keystation 49 MK3 states 49 full-size keys with a width of 32.26 inches.
How to spot full-size keys in a listing
Look for the words full-size in the key description, and check the key count against the width in the spec table. A listing that says mini keys, like the Akai MPK Mini IV with 25 mini keys and the Akai MPK Mini Plus with 37 mini keys, is not full-size. The M-AUDIO Keystation 49 MK3 says full-size keys and lists a width of 32.26 inches.
Match the key count to your desk space
A 49-key controller spans more desk width than a 37-key or 25-key controller, so measure the desk first. The M-AUDIO Keystation 49 MK3 lists a width of 32.26 inches and a weight of 4.9 pounds. The Novation Launchkey 49 MK4 lists a width of 31.69 inches and a weight of 9 pounds. The Akai MPK Mini Plus lists a width of 17.9 inches and a weight of 2.9 pounds, and the Akai MPK Mini IV lists a width of 13.88 inches and a weight of 2.2 pounds.
Check the controls and the connection
Keys are only part of a controller. The M-AUDIO Keystation 49 MK3 has pitch and modulation wheels, a volume fader, transport and directional buttons, octave up and down buttons and a sustain pedal input. The Novation Launchkey 49 MK4 has 16 pads with polyphonic aftertouch, 9 faders, pitch and modulation wheels and an OLED display. The Akai MPK Mini IV has 8 MPC pads and 8 knobs, and the Akai MPK Mini Plus has 8 MPC pads, 8 knobs and a 64-step sequencer. Each controller in this article connects over USB, and the Akai MPK Mini IV uses USB-C.
What you need
M-AUDIO Keystation 49 MK3 USB MIDI Controller
A 49-key controller with full-size velocity-sensitive keys, pitch and modulation wheels, a volume fader and bundled Ableton Live Lite software for recording on a Mac or PC.
- Keys: 49
- Software named in listing: Ableton Live Lite
- USB-MIDI
- 1-year warranty stated
Akai Professional MPK Mini IV 25-Key USB-C
A 25-key controller with mini velocity-sensitive keys, 8 MPC pads, 8 knobs and a full-color screen, with USB-C and a full-size MIDI Out for compact setups.
- Keys: 25
- Pads: 8
- Knobs / faders: 8
- Software named in listing: Ableton Live Lite
- USB-MIDI
- 1-year warranty stated
- 2.2 lb, the lightest here
Novation Launchkey 49 MK4 USB MIDI Keyboard
A 49-key controller with semi-weighted keys, 16 pads with polyphonic aftertouch, 9 faders and an OLED display, with Ableton Live Lite and Cubase LE in the box.
- Keys: 49
- Pads: 16
- Knobs / faders: 9
- Aftertouch
- Software named in listing: Ableton Live
- USB-MIDI
- 3-year warranty stated
Akai Professional MPK Mini Plus 37-Key USB
A 37-key controller with mini velocity-sensitive keys, 8 MPC pads, 8 knobs and a 64-step sequencer, with MIDI and CV/Gate I/O for hardware and modular gear.
- Keys: 37
- Pads: 8
- Knobs / faders: 8
- USB-MIDI
- 1-year warranty stated
These come from our ranked list Best MIDI Keyboard, which compares them spec by spec.
Frequently asked questions
What is the difference between mini keys and full-size keys?
Mini keys are narrower than full-size keys, so the same hand span covers more keys. A player who moves between a controller and a piano may need time to adjust to the spacing. Key size does not change what the controller sends over USB.
How many keys do I need on a MIDI controller?
It depends on the desk space and the parts you play. A 49-key controller covers a wide range in a single row, while a 25-key controller fits a small desk and shifts octaves with buttons. The controllers in this article have 49, 37 and 25 keys.
Do full-size keys need a bigger controller?
Yes. Full-size keys take more width per key, so a 49-key controller with full-size keys is wider than a 25-key controller with mini keys. The M-AUDIO Keystation 49 MK3 lists a width of 32.26 inches, and the Akai MPK Mini IV lists a width of 13.88 inches.
Ranked MIDI keyboards lists
More how-to guides
Product details come from each Amazon listing and can change. Check the listing before you buy.