How to Check Storage on Mac

Checking your Mac's storage is one of those things most people only do once something prompts them to — a "your disk is almost full" warning, an app refusing to save a file, or just a vague feeling that things have gotten slower than they used to be. Whatever the reason, macOS gives you a few different ways to see how much space you've used and how much is left, and they're all built in. No extra software is required just to look.

This guide walks through the three ways to check: the graphical overview in About This Mac, a quick total from Finder, and a Terminal command for anyone who wants the raw numbers. We'll also cover what the categories in that storage breakdown actually mean, and what to do once you know the number.

Why you might want to check

There are a few common reasons people go looking for this information. macOS itself will sometimes throw up a low-storage warning out of nowhere, which is often the first sign anything's wrong. Some people check before starting a big task — installing a large app, importing a video library, setting up a Time Machine backup — to make sure there's enough room. And some people are simply curious after buying a new Mac or handing one down, wanting to know how much of the drive is already in use.

Whatever brought you here, the good news is that checking takes under a minute with any of the methods below, and none of them require installing anything — macOS already includes several ways to see this information, you just have to know where to look.

Method 1: About This Mac

The most common way to check storage is through the Apple menu. Click the Apple logo in the top-left corner of your screen, then choose About This Mac.

Where you go from there depends on which version of macOS you're running, since Apple has moved this screen around over the years:

• On recent versions of macOS, click More Info..., then select General → Storage from the sidebar.
• On older versions (think Big Sur, Monterey, and earlier), there's a Storage tab right at the top of the About This Mac window — click it directly.

Either way, you'll land on the same thing: a colored horizontal bar representing your entire drive, split into segments by category, with a total "X GB of Y GB used" figure above or below it. Hovering over or clicking a segment typically shows more detail about that category.

The categories you'll usually see include:

• Applications — the apps installed on your Mac.
• Documents — a broad bucket covering files in common locations like Desktop, Downloads, and iCloud Drive.
• Photos — your Photos library, including edits and originals.
• Messages — chat history along with any photos, videos, and files sent through Messages.
• System Data (sometimes labeled "Other") — a catch-all for caches, logs, system files, and anything that doesn't fit neatly into the other categories.

This view is genuinely useful for a quick glance, but it's intentionally simplified. It tells you roughly where space is going in broad strokes, not which individual apps or files are the actual biggest users — that takes a different tool, which we'll get to. It's also worth noting that the numbers can take a moment to calculate, especially on a drive with a lot of files, so don't be surprised if the bar takes a few seconds to settle on a final figure the first time you open it.

Method 2: Finder and Get Info

If you just want a fast total — used space and free space, nothing more — Finder can give you that without opening any menus beyond a right-click.

1. Open a Finder window.
2. In the sidebar, click your startup disk (usually named Macintosh HD, though it may have a custom name).
3. Press Cmd+I (or right-click the disk and choose Get Info).

The Get Info window that appears shows Capacity, Available, and Used figures directly. It's less detailed than the About This Mac breakdown — there's no category split here — but it's a fast way to confirm the raw numbers if that's all you need.

Method 3: Terminal (optional, for the technically curious)

If you're comfortable in Terminal, there's an even quicker way to see disk usage, and it's useful if you want to check storage across multiple volumes or disks at once. Open Terminal (found in Applications → Utilities) and run:

df -h

This lists every mounted volume along with its size, used space, available space, and percentage used, all in human-readable units (that's what the -h flag does). It's a raw, low-level view meant for people who want the numbers without any graphical interface around them — most people will be perfectly well served by About This Mac or Finder instead.

How much free space is "enough"?

There's no single official number that applies to every Mac, and it's worth being skeptical of any guide that hands you one as a hard rule. How much free space you actually need depends on what you do with your Mac. macOS itself needs some breathing room to manage virtual memory, temporary files, and system updates, and most apps assume there's at least some free space available to work with — but the exact amount that counts as "enough" scales with usage. Someone editing 4K video or running large virtual machines needs considerably more headroom than someone who mostly browses the web and writes documents.

A more useful signal than any fixed number is behavior: if your Mac feels sluggish, apps are slow to save, or you're seeing low-storage warnings, that's a sign you're pushing against the limit regardless of what the exact free-space figure says. Conversely, a drive that's mostly full but behaving normally with plenty of free space still available isn't automatically a problem just because the percentage looks high.

It also matters whether the space you have left is stable or shrinking. A Mac that's sat at the same used/free split for months isn't in the same situation as one where free space is visibly dropping week over week with no obvious new files to explain it — the second case is worth investigating sooner rather than later.

Now find out what's actually using that space

Once you have a total — whether from About This Mac, Finder, or Terminal — the more useful question is usually "what specifically is using all of that?" rather than just the number itself. If your System Data category looks unexpectedly large, or you're not sure where to even start, our companion article on what's taking up space on your Mac walks through tracking it down category by category. And if the number keeps climbing despite your best efforts at cleaning up, Mac storage almost full, can't find why covers the trickier cases where the obvious culprits aren't the real cause.

Apple's own storage view is a good starting point, but it stops at broad categories. A dedicated Mac storage analyzer goes further, breaking storage down in more detail than About This Mac does and surfacing the actual folders and file types behind each category, so you're not left guessing what "System Data" is hiding.

Checking your storage takes thirty seconds. Understanding what's actually in it is the part worth doing properly — and it's the difference between guessing at what to delete and knowing exactly where to start.