Ledge

How to check the size of files before you send them on a Mac

· 6 min read

To check file size on a Mac, select the file in Finder and press Command-I; the Size line in the Get Info window gives the answer. For several files at once, select them all, hold Option and choose File > Show Inspector (Option-Command-I) to see one combined total. That total is the number to compare against an email or upload limit.

Check one file

  1. Click the file once in Finder to select it.
  2. Press Command-I, or choose File > Get Info.
  3. Read the Size line near the top of the window.

The line shows two figures: an exact count in bytes, then a rounded figure marked “on disk”. The first is the real length of the file and the one that matters when you send it. The second is the space the file occupies on your drive, which is usually a touch larger.

Two quicker glances, when you do not want another window:

  • The preview pane. Choose View > Show Preview (Shift-Command-P). A panel on the right of the Finder window shows the selected file’s kind and size under its name.
  • List view. Choose View > as List (Command-2) and look at the Size column. Click the Size heading to sort largest first, which quickly shows the one photo in a batch that is far heavier than the rest.

Check several files as one total

Pressing Command-I with a handful of files selected opens a separate Get Info window for each one, which is rarely what you want. Use the Inspector instead:

  1. Select the files. Command-click to pick ones that are not next to each other; How to drag files that are not next to each other covers the selection tricks.
  2. Hold Option and open the File menu. Get Info has become Show Inspector. Choose it, or press Option-Command-I.
  3. One window appears, showing the number of items and their combined size.

The Inspector follows your selection. Leave it open, click a different set of files and the total updates. That makes it the fastest way to work out which file to leave behind to get under a limit, and it keeps working as you move from one Finder window to another.

One thing that looks as if it should help and does not: the status bar at the bottom of a Finder window (View > Show Status Bar) counts the selected items and shows the free space on the disk. It does not add up the size of the selection.

Check a folder

Get Info works on a folder too, though Finder may take a moment to count a large one.

In list view, the Size column shows two dashes for every folder by default. To change that, open the folder, choose View > Show View Options (Command-J) and check Calculate all sizes. Finder then fills in a size for every folder in that window. It has to count the contents of each one, so a window full of big folders takes a little longer to settle.

Terminal gives the same answer for any folder. Type du -sh followed by a space, drag the folder into the Terminal window so its path is filled in for you, and press Return. The figure reported is the space the folder uses on disk.

Why the number may not match the limit

A file that looks as if it fits can still be refused. These are the usual reasons.

  • Different rulers. Finder counts 1 MB as 1,000,000 bytes. Some services count 1 MB as 1,048,576 bytes, so the same file can be described with a slightly different number elsewhere. Close to a limit, leave a margin.
  • Email adds overhead. Attachments are encoded for the trip, which makes them roughly a third larger than the file on your Mac. A file only a bit under your provider’s limit can still bounce.
  • Files in iCloud Drive that are not downloaded. A file with a cloud icon beside it may report zero bytes on disk. The first figure on the Size line is still its real size, but download the file before you try to send it.
  • Zipping changes the total. If you plan to send an archive, make it first (Control-click the selection and choose Compress) and check the size of the zip. Text and spreadsheets shrink a lot. Photos, videos and most PDFs barely shrink, because those formats are already compressed.

If the total is too big

Gathering files from several folders

Checking sizes is easy when everything sits in one folder. It gets awkward when the set is scattered: two PDFs in Documents, a scan in Downloads, a photo on the desktop. A workable routine is to keep the Inspector open and weigh each file as you find it, then collect the ones that made the cut.

Ledge helps with the collecting half. Drag each file up to the notch at the top of the screen and let go. It lands on a shelf that drops from the notch and stays there while you go and find the next one, so you never have to keep four Finder windows arranged. When the set is complete, press Option-Space or click the notch to open the shelf, and drag the files into the email or the upload page.

Each destination receives what it can use. A chat app gets the files as uploads, a Finder folder gets the files themselves, and a terminal gets a path as text. Nothing is uploaded along the way; the files stay on your Mac until you drop them somewhere. Ledge needs macOS 14 Sonoma or later, and on a Mac without a notch the shelf sits at the top center of the screen. Batching files for a single upload on a Mac describes the full routine.

Questions

Why does Get Info show two different sizes?

The first is the exact length of the file in bytes. The second, marked “on disk”, is the storage it takes up on your drive. Use the first when you compare against a sending limit.

Does the status bar show the size of the files I selected?

No. It shows how many items are selected and how much free space the disk has. Use the Inspector (Option-Command-I) for a combined size.

How do I see folder sizes in list view?

Open the folder, press Command-J and check Calculate all sizes. The Size column then shows a figure for each folder instead of two dashes.