The Quick Answer
Yes, a Micro-ATX motherboard will fit in an ATX case without any problems. It might look a bit weird depending on your case, but there won’t be any functional issues at all. And there are actually a few benefits to it too, as we discuss later on in this article.
If you’re new to the PC building hobby, you might have asked, “can you put a Micro-ATX motherboard in an ATX case?” It’s a valid question. After all, you want to get it right and not waste money on buying incompatible parts. So let’s look at physical compatibility and the pros and cons of doing so.
Micro-ATX motherboards are physically compatible with ATX cases, as they share most of the same mounting holes as full-size ATX boards. The only difference is in the bottom row, which is in a different location to account for its shorter height (9.6 inches vs. 12 inches for ATX).
Most, if not all, mid- and full-tower ATX cases will have the correct standoff mounts for Micro-ATX’s bottom row. Even if your case doesn’t, there are six mounting holes—C, H, L, F, J, and M in the figure above—shared between Micro-ATX and ATX. So you shouldn’t have problems mounting an mATX board securely even if your case doesn’t support mATX-specific mounting holes.
You won’t need to worry about the expansion slots being in the right place, either; the top PCIe x16 slot is in the same place regardless of motherboard size. This standardized position avoids the possibility of a motherboard being too small to reach a case’s expansion slots.
So there you have it: a Micro-ATX motherboard will fit in an ATX case no problem and work fine. Now that that’s resolved, let’s take a quick look at why you might want to do this, plus one potential issue you may face.
Pros of Using an mATX Motherboard in an ATX Case
With all the great Micro-ATX cases available these days, you may be wondering why anyone would want a bulkier and more expensive ATX case for their mATX motherboard. One big reason to go for the larger case is to have a bit of future-proofing if you decide (or have) to upgrade to an ATX board down the line.
Using a Micro-ATX case means you’re stuck with the smaller form factor unless you buy a new case with your new motherboard. This makes a motherboard upgrade more expensive than it needs to be, for one. It also means you’ll be spending a lot of time transplanting all your components to a new case.
Neither are huge problems, but they can be easily avoided by going for a larger case in the first place. So before you choose a PC case, take some time to think about your plans and whether you might ever want to upgrade to a standard ATX motherboard soon. If yes, then it’s worth considering a mid- or full-tower case to make things easier in the future.
But what if you’re in the opposite situation? Maybe you already have an ATX case and need to decide on a motherboard. If so, you may want to consider an mATX board because they’re often more affordable than ATX boards.
Don’t get us wrong; there are plenty of expensive mATX motherboards that cost as much as (or more than) a comparable ATX board. But if you need to get a rig up and running for cheap, you’re more likely to find something suitable in the mATX form factor. Take this Gigabyte B450 motherboard, for example:
Yes, it’s on an older chipset. And no, it’s not very high-end. But it’s around $30 less than the cheapest B450 ATX motherboard, a significant saving if you’re shopping at the more affordable end of the market.
Of course, this is only an option if you don’t need the extra PCIe expansion slots. You likely won’t if you’re building a straightforward gaming rig with a single GPU. But if you need additional slots for capture cards or sound cards, then an ATX board might still be the better choice. So it all depends on what you’re doing with your rig.
The Only Con: Aesthetics
Micro-ATX boards are 2.4 inches shorter than ATX boards, so you’ll have empty space at the bottom of your case if you opt for the smaller board. Depending on your case layout and color, this can either be an eyesore or something totally unnoticeable.
This won’t be an issue in a modern case with a black interior. A PSU shroud and a two- or three-slot graphics card mean that you likely won’t notice the shorter motherboard unless you look at it from a low angle (example above).
However, it’s not quite as easy to overlook in budget (or old) ATX cases without PSU shrouds. Here, the empty space is hard to ignore, making the build look a bit cheap:
Of course, this is all subjective. There’s no right or wrong here, and it will all come down to your preferences. We don’t think aesthetics is a particularly strong reason to avoid (or go for) installing an mATX board in an ATX case, but we’ll leave that decision up to you.
The answer to the question “can you put a Micro-ATX motherboard in an ATX case?” is simple: yes, you can. Whether you should or shouldn’t is less straightforward, and you’ll have to decide that for yourself. Just remember that there aren’t any performance issues to worry about, so go for whichever form factor suits your current and future needs best.
If you’re just looking around and aren’t sure which motherboard size to go for, check out our guide to the three main motherboard form factors for some good info.