QMK and ZMK are the two major open-source firmware options in the mechanical keyboard world, yet they are built upon fundamentally different design philosophies. QMK originated in the era of wired keyboards; while it boasts a mature ecosystem and a rich feature set, its Bluetooth support has remained in the experimental stage. In contrast, ZMK was designed from day one for wireless keyboards. Built on the Zephyr RTOS, it offers native support for Bluetooth Low Energy (BLE) and tiered sleep management. This architectural difference translates directly into performance metrics: the Keychron Q Ultra series, powered by ZMK firmware, achieves a 660-hour battery life in wireless mode with an 8000Hz polling rate, whereas QMK-based wireless keyboards with identical battery capacities typically manage only 100 to 190 hours.
I. QMK: The Gold Standard of the Wired Era
QMK (Quantum Mechanical Keyboard) is the most mature open-source firmware in the mechanical keyboard space, having branched off from TMK firmware in 2015. Its ecosystem advantages are virtually unrivaled: it supports a wide range of MCUs—from 8-bit AVR to 32-bit ARM—and offers real-time key-remapping tools like VIA and Vial. Its features—including layers, macros, Tap Dance, and Combos—cover virtually every conceivable input scenario.
For years, «QMK/VIA compatibility» has served as a de facto seal of approval for keyboard customizability. Mainstream manufacturers such as Keychron, KBDfans, and Drop have adopted QMK as their default firmware; on GitHub alone, Keychron’s QMK repository has garnered over 43,000 stars.
However, QMK suffers from a structural limitation: its architecture was designed for wired keyboards. Bluetooth support remains experimental, and the GPL license makes the integration of proprietary wireless drivers structurally difficult. Consequently, wireless keyboards utilizing QMK often require a «dual-chip» solution—one MCU handles keyboard logic, while a separate chip manages wireless communication. The Keychron K8 QMK V2 is a prime example: despite upgrading to Bluetooth 5.2, its officially rated battery life is only 190 hours with backlighting off and 100 hours with it on—showing no fundamental improvement over its predecessor. The additional power consumption and hardware complexity introduced by multi-chip designs are among the fundamental reasons for the limited battery life of QMK-based wireless keyboards.
II. ZMK: An Architecture Built from the Ground Up for Wireless
ZMK (Zephyr Mechanical Keyboard) starts from a completely different premise. Built upon the Zephyr RTOS, ZMK directly inherits the fruits of the Zephyr project’s BLE protocol stack development and maintenance; keyboard firmware developers do not need to implement or maintain the low-level Bluetooth stack themselves. ZMK’s official objective is clearly stated: «Designed for power efficiency, flexibility, and broad hardware support.»
Low power consumption is a core priority in ZMK’s architectural design, not an afterthought or a patch. ZMK offers a tiered power management system:
— Idle State: Automatically entered after 30 seconds of inactivity by default. Peripherals such as displays and lighting are turned off, but the Bluetooth connection remains active, allowing for immediate response to key presses.
— Deep Sleep State: The keyboard enters a software-controlled power-down state. All Bluetooth connections are severed, peripherals are disabled, and RAM is cleared, resulting in extremely low power consumption. Waking up requires a few seconds to re-establish connections, making this mode suitable for periods of prolonged inactivity.
— Soft Off State: The keyboard is explicitly turned off via a key combination or a dedicated button. Wake-up sources are more restricted than in Deep Sleep, yet power savings are comparable; this serves as a software-based alternative to a physical power switch.
Additionally, ZMK supports cutting off VCC power to peripherals like RGB LEDs and OLEDs, eliminating standby power consumption at the hardware level. Regarding Bluetooth management, ZMK supports five pairing profiles by default—allowing users to quickly switch between multiple devices—and implements a secure pairing mechanism based on BLE Secure Connections.
III. The Energy Efficiency Divide: The Data Speaks
The gap in energy efficiency between QMK and ZMK is clearly evidenced by data at the product level.
The Keychron Q Ultra series serves as a prime example. Powered by ZMK firmware, this series boasts an official battery life of 660 hours in wireless mode with an 8000Hz polling rate. In contrast, the Keychron Q Max series—which utilizes QMK firmware and shares the same 4000mAh battery capacity—offers a battery life of approximately 180 hours. Since battery capacities are identical, the disparity stems from differences in firmware architecture and wireless design.
Another comparison offers an even more direct illustration. The Keychron B2 Pro utilizes ZMK firmware, allowing its 800mAh battery to deliver approximately 300 hours of usage; in contrast, the QMK-powered Keychron Q1 Max, with a 4000mAh battery, offers only about 100 hours of battery life when the backlight is turned off. Although the two products differ in market positioning and hardware specifications, the disparity in energy efficiency is stark and telling.
ZMK’s energy efficiency advantage stems not from a single «power-saving feature,» but from systemic design choices at the architectural level: a single-chip wireless SoC replaces a dual-chip setup; a native BLE protocol stack replaces an external Bluetooth module; tiered sleep management replaces crude power control; and RTOS-level peripheral power management replaces manual configuration.
IV. The Other Side of ZMK: Ecosystem Gaps and the Learning Curve
ZMK is not without its shortcomings. Its ecosystem maturity still lags behind that of QMK. While QMK boasts mature real-time key-remapping tools like VIA and Vial, the ZMK equivalent—ZMK Studio—is still evolving. For users accustomed to «drag-and-drop key remapping in a browser,» ZMK presents a steeper learning curve.
Regarding language layout support, QMK covers a wider range of keyboard layouts than ZMK. A 2026 comparison shows that QMK supports layouts such as `us_extended`, `us_international_linux`, Japanese, and Korean, whereas ZMK’s list of layouts is relatively shorter. Users relying on non-English keyboard layouts have a broader range of options with QMK.
However, ZMK is catching up rapidly. Keychron Launcher now supports browser-based key remapping for both QMK and ZMK keyboards, lowering the barrier to entry for ZMK configuration. As products like the Keychron Q Ultra and K1 Ultra 8K introduce ZMK to a wider user base, the ecosystem gap is gradually being bridged.
V. Selection Logic: Choose QMK for Wired, ZMK for Wireless
By 2026, the division of roles between these two firmware options has become quite clear.
Scenarios for choosing QMK: wired keyboards, a need for extreme customization capabilities, reliance on VIA/Vial for real-time key remapping, use of non-English keyboard layouts, and a preference for mature community documentation and troubleshooting resources. ZMK is the right choice if you are looking for a wireless keyboard with long battery life, require native Bluetooth multi-device switching, utilize a low-power wireless SoC, and are open to a relatively young yet rapidly growing ecosystem.
Keychron’s product line shift sends a clear signal to the industry: the Q Ultra and K Ultra series are fully transitioning to ZMK, while the traditional wired Q series continues to use QMK. This does not mean QMK is being phased out; rather, each firmware has found its ideal niche. For wireless keyboards, ZMK has evolved from merely an «option» to the «default choice.»
