Azio IZO Numpad vs MMD KM21 Ultra
Choose the Azio IZO Numpad for its standalone calculator and double-shot PBT keycaps, or the MMD KM21 Ultra for its four clickable knobs, QMK/VIA customization, and aluminum case.
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Which one should you get?
Get the
Azio IZO Numpad
Battery
Build quality in the bottom 15% of Numpad boards under $100.
- Functions as a standalone calculator with calculator-specific function keys.
- Double-shot PBT keycaps and nine backlight modes.
- Bluetooth mode can connect to up to three devices.
Get the
MMD KM21 Ultra
Knob
Build quality in the top 15% of Numpad boards under $100.
- Four clickable knobs alongside 17 hot-swap keys, configurable through QMK/VIA.
- CNC-milled aluminum case with top-mount construction.
- PORON, IXPE, PET plate, and bottom-foam damping.
Choose the Azio IZO Numpad if you want a standalone calculator, double-shot PBT keycaps, and Bluetooth pairing for up to three devices. Choose the MMD KM21 Ultra if you want four clickable knobs, QMK/VIA customization, and an aluminum case with layered damping. Both are hot-swappable numpads with wireless and wired connectivity, but their additional controls serve different needs.
The differences that matter
Skip the 40-row spec sheet. These are the specs that change how each board feels, sounds, and fits your desk.
Azio IZO Numpad
MMD KM21 Ultra
Connection
Bluetooth, Wired
Bluetooth, 2.4 GHz, Wired
Wireless for several devices and wired for lower latency
Battery
1,000 mAh
980 mAh
A larger battery means fewer cables during the day
Case material
Plastic
Aluminum
Knob
No
Yes
QMK
No
Yes
The deep option when you want to remap every key
- Azio IZO Numpad
- MMD KM21 Ultra
- Performance
- 5866
- Build quality
- 4781
- Productivity
- 5989
- Customizability
- 5489
- Portability
- 8685
- Layout size: Numpad
- Hot-swappable
What will you mostly use it for?
The KM21 Ultra has the clearer edge for gaming shortcuts, programming controls, modding, and creative workflows because it combines knobs with QMK/VIA support. Office use is a split: the IZO's standalone calculator is useful for calculation-focused tasks, while the KM21 Ultra offers configurable controls. For travel, both provide wireless operation, and the IZO's listed weight gives a specific portability reference, while no KM21 Ultra weight is listed.
Pick the MMD KM21 Ultra
- The KM21 Ultra's QMK/VIA support and four clickable knobs provide configurable controls for shortcuts and macros.
- It supports USB-C, 2.4 GHz wireless, and Bluetooth connections.
Azio IZO Numpad vs MMD KM21 Ultra specs
Every tracked spec, side by side. Rows marked with a dot differ between the boards.
10 of 23 specs differ
Azio IZO Numpad
MMD KM21 Ultra
Switch options
Hot-swappable
Mount style
Sound dampening
Layout size
Layout standard
Ergonomics
Knob
Display
Connection
Battery
USB-C
Case material
Plate material
Keycaps
Weight
Dimensions
Backlight
QMK
VIA
N-key rollover
Mac & Windows
Released
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Azio IZO Numpad vs MMD KM21 Ultra: your questions
Yes. Azio describes it as a standalone calculator when it is not being used as a number pad, with calculator-specific function keys. The KM21 Ultra is described as a configurable numpad and macropad.
Yes. It has four clickable knobs in addition to 17 hot-swap keys. The vendor describes using knobs for controls such as volume, zoom, scrolling, and timeline scrubbing.
The MMD KM21 Ultra lists QMK and VIA support. Its vendor description says keys and knobs can be assigned through VIA, including for macros and layers.
Both products list hot-swap support. The KM21 Ultra comes with MMD Cream linear switches, while Azio's vendor page describes Gateron Red linear switches.
Azio says the IZO can connect to up to three devices in Bluetooth mode. Its listed connectivity also includes wired and wireless operation.
The KM21 Ultra supports Bluetooth, 2.4 GHz wireless, and wired USB-C. The vendor lists a 980 mAh battery and includes a 2.4 GHz wireless receiver.
The MMD KM21 Ultra has a CNC-milled aluminum case and a plastic plate. The Azio IZO Numpad lists a plastic case and PBT keycaps.
Yes. Its metadata lists PBT keycaps, and Azio describes them as double-shot PBT. The vendor page also lists nine backlight modes.
The MMD KM21 Ultra has four clickable knobs, and its vendor describes them for uses such as timeline scrubbing and zoom. QMK/VIA support lets users configure the controls for their workflow.
Yes. Both list wired connectivity and USB-C. The KM21 Ultra also lists 2.4 GHz wireless, while the IZO vendor describes switching between wired USB and Bluetooth modes.
The Azio IZO Numpad has a listed weight of 221 g. A weight is not listed for the MMD KM21 Ultra, so the available specifications do not establish a weight comparison.
Yes. Its 17 keys and four clickable knobs are described as configurable through QMK/VIA for shortcuts, macros, and layers. That makes it the more explicitly configurable option compared with the IZO's calculator-focused extra function.
Not sold on either?
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