1. The clearances that matter
Clearance problems are the classic reason a build is returned: the parts fit the socket, the power rails and the slots, but not the space inside the case. Each clearance below is a comparison between two listed dimensions — the part’s own listing and the case’s limits — and the manufacturer documentation carries both values.
- CPU cooler height for air coolers, or radiator and fan space for liquid coolers.
- Graphics card length and thickness, against the case’s maximum card length.
- Memory height under the cooler, where a wide cooler can overhang the slots.
- Power supply length and cable room at the back of the case.
2. Air cooler height against the case
The cooler’s product page lists its height, and the case’s page lists the maximum cooler height it accepts. Both are nominal dimensions published by different manufacturers, so a value that matches on paper can still be tight in practice. Leaving margin is part of the check, not an afterthought.
- The cooler’s product page lists its height; the case’s page lists the maximum cooler height.
- The cooler must be at most the case’s maximum; dimensions are nominal, so leave margin.
- Wide coolers can overhang the memory slots; see the memory height section before you assume a tall cooler will clear them.
3. Liquid cooler radiators
A liquid cooler’s radiator occupies space at the front, top or rear of the case, and the case manufacturer lists which radiator sizes fit in which position. Thickness is the dimension that trips people up: whether the fans are included in the stated thickness depends on how the cooler’s figures are given, so read them the same way the case’s limits are stated.
- The case’s page lists which radiator sizes fit in which position (front, top, rear).
- Thickness includes the fans; check the cooler’s listed radiator thickness against the position you plan to use.
- A top radiator can collide with memory or motherboard heatsinks, so treat a top mount as an extra check rather than an automatic fit.
4. Graphics card length and thickness
Compare the card’s listed length with the case’s maximum graphics card length, and remember that the maximum assumes a clear front of the case. Front fans or a front radiator reduce the length actually available, and a thick card can cover neighbouring slots even when the length is comfortably within the limit.
- Compare the card’s listed length with the case’s maximum graphics card length.
- Front fans or a front radiator can reduce the available length; check what you plan to install before you trust the maximum.
- A thick card covers neighbouring slots; How to choose a graphics card has the card-side dimensions to compare against.
5. Memory height and cooler overhang
Memory modules have a listed height, and some coolers sit over or beside the first memory slot, limiting how tall a module can be there. The cooler’s page often says whether it limits memory height; where it does not, the memory kit’s own listing is the reference to keep alongside the cooler’s.
- Memory kits list their module height; some coolers sit over the first memory slot.
- The cooler’s page often says whether it limits memory height; check it before you pair the two.
- Where the cooler’s documentation is silent, compare the listed heights against each other and leave margin.
6. Power supply length and cables
The case’s documentation lists the power supply clearance, and the supply’s product page lists its length. The cables need their own space as well: a supply that fits on paper but leaves no room for its cables to bend will not hold together once the build is closed up.
- Compare the power supply’s listed length with the case’s power supply clearance.
- Leave room for the cables to bend; Power supply wattage and connectors covers the supply side of the build.
7. What this site checks, and what it does not
This site compares what it can from manufacturer documentation and leaves the rest visible as unknown. Form factor matching is checked; physical clearance is not, because it depends on the exact models in your case and on how the cables end up routed.
- Use the builder to compare motherboard form factor and power supply form factor with what the case supports.
- Physical clearance is not checked; the product pages show listed dimensions only where we have read them, and the compatibility page explains what is and is not checked.
- Browse cases and coolers in the parts catalogue: cases and coolers.
Sources and scope
This guide gives a checklist, not a product recommendation or a hands-on test. It relies on the specifications published by manufacturers, so always confirm details on the manufacturer’s product page for the exact model you are buying. Read how our guides are researched for the standard this site applies to all of its buying advice.