Thursday, July 29, 2010

File size limit of 4GB in FAT32 file system

Many of u may not be familiar with this that there is a file size limit of 4GB in file system( or more technically its 3.99 GB)... Even i am a years old FAT32 system user yet i had no idea abt it till recently!!!

There are two well explained reason behind not knowing abt it, first being that most of us have switched to the modern file systems such as exFAT/FAT64, NTFS or NTFS5... Second reason being we pretty rarely come across with the files larger than 4GB, and even if we come across them the are split into volumes of smaller sizes,so we may not know abt them... And the last and most common reason we actually never cared!!!

Reason for the file size limit lies in the design itself the FAT32 system was designed on the basic FAT systems and took it to a much higher limit from the parent version.. This file system's maximum limiting size on stored files is set by its inherent design considerations. The FAT32 file size limit is only 4 GB minus 1 byte (232 - 1 bytes). This limitation was imposed because with greater volume sizes, data transfers becomes too slow under FAT32 format..
Hence in that case Microsoft wanted us to use the other advanced file systems...

The newer systems provided better security features, better file management, stability, speed, support for large hard disks, compression and above all about unlimited file size and cluster size... The latest of the file systems is NTFS5, which is a slight improvement from the previous version of NTFS, more about this will be in my next blog.. Till then u'll have to wait!!!

Here is a picture of the files larger than 4GB and how they are splitted in parts of 3.99GB in a FAT32 system:

Here's a list of file systems and their file size limits:

  • FAT12: 16MB
  • FAT16: 2GB
  • FAT32: 4GB minus 1 byte
  • exFAT/FAT64: 16ZB
  • NTFS: 16TB minus 64KB
  • NTFS5: 16 ExaBytes minus 1KB
sources: Microsoft support center

As this was my first blog, i apologize if i made a mistake in writting anything, and suggestions are alwayz welcomed... As of the blog i understand its too small, but i have been typing and posting everything through cellphone(since i m having a bandwidth problem), n u all must know how irritating its to type on a cellphone, yet i have tried to make the post a better one... Hope u like it...


  1. First of all, great work Mayank, because I can easily say that you wrote it all yourselves, which is commendable.

    I was about to say about "txt spk" like "u" instead of "you", but as you said you were typing on a cell phone, so I can understand your frustration. Maybe you can edit it later on a PC and re-write it?

  2. Considering that it has been typed on a phone, it's very well written. Also, by writing it yourself, and not using words that were probably used on the sites that you used for research, you made it a lot easier to understand too! :)

    And I personally think it's a good thing that you kept the post size short because reading very long posts becomes tedious. :P

  3. Microsoft does not impose a limit on the file size. It only imposes a size limit on the file system itself. That too, only for creation, and not for reading/writing.
    The 4GiB - 1B file size limit on FAT32, although correct, isn't because of the reason you mentioned.
    Before you post anything, please make sure that it is correct.