Your 256 GB Mac says 245 GB: where the missing space went
A new Mac never shows its full advertised size. How much goes to recovery and system partitions, how much to macOS, and how to see each piece for yourself.
You bought a 256 GB Mac. Disk Utility says about 245 GB, and on day one only around 220 GB or less is free. None of that is a fault. It is the sum of three small things.
1. The label counts differently
Storage makers count 1 GB as 1,000,000,000 bytes. macOS counts the same way, so this does not explain much on a Mac, unlike on Windows where the same drive shows as 238 GB because Windows counts in powers of 1,024. It is why numbers disagree between computers.
2. Hidden partitions
Apple silicon Macs keep a small system container and a recovery container outside your main one. Together they are a few GB. That is most of the gap between 256 and about 245.
diskutil list internalYou will see the main container, around 245 GB on a 256 GB Mac, and smaller entries for the system and recovery parts.
3. macOS and its volumes
Inside the main container, macOS has its own sealed system volume, plus Preboot, Recovery and VM volumes. The system alone is typically 10 to 15 GB. How much space macOS takes and Other Volumes in the container break that down.
| Part | Roughly |
|---|---|
| Advertised | 256 GB |
| Main container you see in Disk Utility | About 245 GB |
| macOS system volume | 10 to 15 GB |
| Preboot, Recovery, VM | A few GB, more with large swap |
| Left for you on day one | Around 220 to 230 GB |
After that, apps you install and the Library data that builds up start to use the rest. What uses space on a new Mac covers the first weeks.
Common questions
Why does my 256 GB Mac show only 245 GB?
A few GB go to hidden system and recovery containers outside the main one. Disk Utility shows the main container, which is around 245 GB.
How much free space should a new 256 GB Mac have?
Roughly 220 to 230 GB on the first day, after macOS and its hidden volumes. Preinstalled apps and updates reduce it a little from there.
Why does the same drive show a different size on Windows?
Windows counts a GB as 1,073,741,824 bytes, while macOS and drive makers count 1,000,000,000. The same drive shows a smaller number on Windows.