So this is what i did:

  • I partitioned my drive and created a 128GB free volume.

  • I Installed Ubuntu choosing Install Ubuntu alongside Windows and not Something else (it didn't ask me in which partition I wanted to install Ubuntu and it installed it anyways, where did it install? in my 128GB partition?)


After installation in Ubuntu it says it can hold 134GB but the partition was of only 128GB, so from where did it get the other space?

disk info

Partitions in Windows:

Partitions in Ubuntu:

They are different. Why? How?

  • Please add code and data as text (using code formatting), not images. Images: A) don't allow us to copy-&-paste the code/errors/data for testing; B) don't permit searching based on the code/error/data contents; and many more reasons. Images should only be used, in addition to text in code format, if having the image adds something significant that is not conveyed by just the text code/error/data. – double-beep May 19 at 13:54

The confusion here comes from the inconsistent usage of two unit prefixes, metric/SI and binary.

Technically correct would be:

  • 1 GB = 1 Gigabyte = 1000³ byte = byte
  • 1 GiB = 1 Gibibyte = 1024³ byte = 1.073.741.824 byte

Unfortunately the term Gibibyte is not very commonly used, at least colloquially, and instead Gigabyte (or GB) is often used for both the metric and the binary unit, leading to slightly different numbers.

In your case, the Ubuntu Devices GUI reports the size of the file system as 134.2 GB whereas lsblk and the Windows disk manager show 127.5 GiB for the partition size. Doing the maths on that:

Partition (lsblk/Windows):   127.5 GiB = 127.5 * 1024³ bytes = 136.902.082.560 bytes  
File system (Disks GUI):     134.2  GB = 134.2 * 1000³ bytes = bytes

The remaining difference of around 2.7 GB could be due to rounding errors and/or that the Ubuntu Disks GUI already subtracted some space for file system structures etc. from the total space.

You can get the exact partition size in bytes with e.g. lsblk -b. That number should 100% accurately reflect the outer size of the partition, with no unit conversion or rounding going on and without taking anything about the contained file system into account.

The exact total inner size of the file system in bytes should be reported by df -B1. It is slightly smaller due to the mentioned internal file system structures etc. taking up some space too.


128 * 1.024 * 1.024 = 134.2, maybe it's due to the difference between Gigabytes and Gibibytes.

  • Thasks, I think the same! How do i confirm this? – john jody May 18 at 15:40

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