Organising files

Making Finder show folder sizes

Updated 2026-07-31 · 3 min read

Finder shows '--' for folder sizes until you find one checkbox, and even then it is not the whole story.

The checkbox

In a Finder window: View → Show View Options (⌘J) → tick Calculate all sizes. List view then shows real folder sizes and can sort by size — which is the point, since finding the heavy folder is the whole job.

The setting is per-folder by default; Use as Defaults at the bottom applies it everywhere.

Why sizes appear slowly

Finder walks each folder tree to sum it, so big folders fill in late. It caches results, so subsequent visits are faster.

Get Info alternatives

Select a folder → ⌘I shows its size. Select several → ⌥⌘I opens a single inspector that updates with the selection — quicker than opening ten Info windows.

The Terminal, for truth and speed

du -h -d 1 ~/Projects | sort -hr

Sizes every immediate subfolder, sorted. du counts what Finder sometimes cannot see (hidden files) and is the only way to size protected areas:

sudo du -h -d 2 /Library 2>/dev/null | sort -hr | head

Discrepancies you will meet

• Finder reports logical size; disk usage is allocation — thousands of tiny files

occupy more than they sum to

• APFS clones make two copies of a file count twice logically while occupying once
• Evicted iCloud files count in Finder's size but occupy nothing

When numbers disagree, du reflects the disk; Finder reflects the files. Both are right about different questions.

Common questions

How do I sort folders by size in Finder?

Turn on Calculate all sizes in View Options (⌘J), then sort list view by the Size column.

Why does Finder show -- for folder sizes?

Sizing a folder means walking it. Finder does so only when Calculate all sizes is on.