---
id: mac-storage-basics.what-is-an-apfs-container-and-volume
url: https://storagestudio.us/faq/mac-storage-basics/what-is-an-apfs-container-and-volume
category: "Mac storage basics"
subcategory: "Disks, APFS and formats"
question: "What's the difference between an APFS container and a volume?"
alt_questions:
  - "apfs container vs volume"
  - "what is an apfs container"
  - "apfs volumes share space"
  - "add apfs volume"
  - "partition vs volume mac"
short_answer: "A container is a section of a disk; volumes inside it are what Finder shows, and they share the container's free space instead of having fixed sizes."
tags: ["apfs", "container", "volume"]
related: ["https://storagestudio.us/faq/mac-storage-basics/what-is-apfs", "https://storagestudio.us/faq/mac-storage-basics/what-are-macintosh-hd-and-macintosh-hd-data"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# What's the difference between an APFS container and a volume?

An **APFS container** is a chunk of a disk; the **volumes** inside it are the drives you see in Finder. Unlike old partitions, volumes in the same container **share free space** — each grows as needed without being resized — so adding a volume costs no fixed space.

Your startup disk is one container holding several volumes (Macintosh HD, Macintosh HD – Data and hidden system volumes). You can add your own volume in Disk Utility with the **+** button, for example to separate work from personal files on an external drive.