Compact PC builds have never been more popular, and whether you are working with a tight desk setup, building a living-room machine, or simply want a cleaner, smaller rig, a compact Micro-ATX or small-form-factor case is the obvious starting point. This year the market has shifted noticeably: manufacturers have borrowed dual-chamber layouts and tempered glass panels from premium full-tower designs and squeezed them into cases costing well under £100. Airflow has also improved dramatically, with mesh-front designs and pre-installed ARGB fans now appearing at price points that would have seemed impossible two years ago. This roundup is aimed at builders who want a genuinely capable compact enclosure without stretching the budget, covering Micro-ATX and compact ATX cases that keep a small physical footprint. Every pick here sits under £100 and has been chosen for real-world build quality, thermal performance, and value for money in the UK market.
Quick Verdict
Best Overall: Lian Li O11 Dynamic Mini V2. It combines a dual-chamber layout, excellent cable management, and Lian Li's proven build quality in a compact ATX footprint that punches well above its price.
Best Value: MSI MAG FORGE 100R. At under £40 it offers tempered glass, decent airflow, and a clean interior that most budget builders will find hard to fault.
The Lian Li O11 Dynamic Mini V2 is the best overall pick in this roundup, and it earns that title by combining a dual-chamber layout, exceptional build quality, and a genuinely flexible interior design in a compact ATX form factor that sits just under £76. The O11 Dynamic is one of the most iconic PC case designs of the past decade, and the Mini V2 brings the core principles of that design, including the dual-chamber layout and the panoramic glass viewing angle, to a smaller, more affordable package.
The dual-chamber design separates the PSU and cable management from the main motherboard and GPU compartment, which results in a dramatically cleaner interior appearance and significantly better airflow. Hot air from the GPU and CPU is not mixed with the warm air from the PSU, and cables are routed entirely out of sight behind the motherboard tray. The result is a build that looks genuinely impressive through the dual tempered glass panels, which provide a wide viewing angle from both the front and the side.
Internally, the O11 Dynamic Mini V2 supports compact ATX, Micro-ATX, and Mini-ITX motherboards. GPU clearance is up to 360 mm, CPU cooler height up to 155 mm, and PSU length up to 200 mm. Three 120 mm fans are pre-installed, and the case supports up to six 120 mm fans or a combination of radiators, including a 360 mm radiator on the side and a 240 mm radiator at the bottom. This makes the O11 Mini V2 one of the most capable cases for custom water cooling in this price range.
The front panel I/O includes USB 3.0, USB-C, and audio jacks. The build quality is, as expected from Lian Li, excellent: the steel is thick and rigid, the tempered glass panels are precisely fitted, and every detail of the interior layout reflects careful engineering. Cable management is the best in this roundup, with generous routing channels, velcro straps, and a PSU chamber that accommodates even the longest modular power supplies without difficulty.
The O11 Dynamic Mini V2 is not the smallest case in this roundup, and its dual-chamber design means the overall footprint is wider than a conventional compact case. For builders who prioritise desk space above all else, the Montech or MSI options may be more suitable. For everyone else, the O11 Mini V2 offers a level of build quality, flexibility, and visual impact that is simply unmatched at this price.
Verdict: The best compact case under £100 in the UK. The dual-chamber layout, premium build quality, and exceptional cable management make it the clear overall winner.
Pros
- Dual-chamber layout eliminates cable clutter from the main viewing compartment
- Dual tempered glass panels provide a panoramic view of the build from two angles
- Supports 360 mm radiator mounting, making it ideal for AIO and custom water cooling
- Lian Li's build quality is the best in this price bracket, with thick steel and precise panel fitment
Cons
- Wider footprint than conventional compact cases due to the dual-chamber design
- CPU cooler height limit of 155 mm excludes some larger tower coolers
How We Picked
Every case in this roundup was selected based on a combination of hands-on assessment, verified UK pricing, and real-world build testing. We assessed each case across five core criteria: build quality and materials, interior layout and component clearances, included fans and cooling potential, cable management provision, and front panel I/O. Price was treated as a hard constraint: every case had to be available in the UK for under £100 at time of writing. We also considered the range of supported motherboard form factors, giving additional weight to cases that accommodate both Micro-ATX and Mini-ITX boards. Cases were tested with a representative mid-range build, including a 240 mm AIO cooler, a 280 mm GPU, and a modular PSU. Thermal and noise measurements were taken at both idle and load. Brand reputation and long-term availability of spare parts were also factored into our final rankings.
Buying Guide
Form Factor: Know What Your Motherboard Needs
The single most important consideration when buying a compact PC case is motherboard compatibility. Micro-ATX motherboards measure 244 x 244 mm, while Mini-ITX boards are smaller at 170 x 170 mm. Most cases in this roundup support both, but you should always check the manufacturer's specification before purchasing. A case listed as Micro-ATX will typically also support Mini-ITX, but not the other way around. If you are planning to use a standard ATX board, the Fractal Design Epoch XL is the only case in this roundup that accommodates it.
Airflow: Mesh vs. Glass
There is a fundamental trade-off between airflow and aesthetics in compact PC cases. Full-mesh front panels, as found on the Montech AIR 903 MAX, allow maximum air intake but also allow more fan noise to escape. Solid or semi-mesh front panels reduce noise but can restrict airflow, leading to higher component temperatures. For a high-performance gaming build with a powerful GPU, a mesh front panel is strongly recommended. For a quieter home office or living-room build, a semi-mesh or solid front panel with good fan configuration may be preferable.
Cooling Capacity: Fans and Radiators
Check how many fans the case supports and what radiator sizes are compatible. If you plan to use an AIO liquid cooler, you need to ensure the case can accommodate the radiator size you have in mind. A 240 mm AIO is the most common choice for compact builds and is supported by all cases in this roundup. A 360 mm AIO requires a larger front mount, which is only available on the Lian Li O11 Dynamic Mini V2 in this selection. Pre-installed fans are a genuine cost saving: a set of three decent ARGB fans can add £20 to £40 to a build budget.
Cable Management: Plan Before You Buy
Cable management is harder in compact cases than in full towers, and the quality of the routing channels and behind-tray space varies significantly across this price range. Lian Li and Fractal Design cases consistently offer better cable management than budget alternatives. If you are using a non-modular PSU, expect to spend more time managing cables regardless of which case you choose. A modular or semi-modular PSU is strongly recommended for any compact build.
Front Panel I/O: USB-C Matters
USB-C on the front panel has become an expected feature in 2025, but it is still absent from the cheapest cases in this roundup. If you regularly connect USB-C devices, a phone, an external SSD, or a camera, the presence of a front USB-C port will save you reaching around to the back of your PC every time. The Montech AIR 903 MAX, Lian Li A3-mATX, Fractal Design Epoch XL, and Lian Li O11 Dynamic Mini V2 all include USB-C front I/O.
GPU Clearance: Check Before You Buy
Modern high-end GPUs are large. A current-generation card from AMD or Nvidia can easily exceed 320 mm in length and occupy three expansion slots in width. Before purchasing a case, check the maximum GPU length against your intended graphics card. The Montech AIR 903 MAX offers the most generous GPU clearance in this roundup at 380 mm, while the Lian Li O11 Dynamic Mini V2 and Lian Li A3-mATX both accommodate up to 360 mm. The MSI MAG FORGE 100R is the most restrictive at 330 mm, which is still sufficient for most mid-range GPUs.
Final Verdict
The Lian Li O11 Dynamic Mini V2 is the clear overall winner in this roundup. Its dual-chamber design, dual tempered glass panels, excellent cable management, and Lian Li's consistently high build quality combine to produce a compact case that is genuinely difficult to fault at under £80. It is the case we would recommend to any builder who wants a compact, visually impressive, and thermally capable enclosure without breaking the budget.
For builders on the tightest possible budget, the MSI MAG FORGE 100R remains the best value pick. It lacks the premium features of the Lian Li, but at under £40 it offers a tempered glass panel, solid construction, and enough internal space for a capable mid-range build. If airflow is your primary concern and you are willing to spend around £60, the Montech AIR 903 MAX's full-mesh design and four pre-installed fans make it the best thermal performer in this price range. And for builders who want something genuinely different, the Lian Li A3-mATX Wood Edition's distinctive front panel and premium build quality make it a compelling choice that stands apart from every other case in this roundup.
