Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

What are the theoretical and practical minimum sizes for a FAT16 volume?

I'm trying to determine the smallest Flash-chip size that can handle a FAT16 FS.

share|improve this question
up vote 4 down vote accepted

If I remember correctly it's 4.1MiB (1,048,576 bytes*4.1 = 4,299,161.6 bytes).

share|improve this answer
That's correct. It is either 4.1MiB or equivalently 4.3MB. If you would also like the max size, it is (on a NT/2000/WinXP machine) 4GiB or 4.29GB. – Marcin Nov 23 '09 at 19:06
Ah! So it makes sense that my FAT driver throws error at about 4MB. Where does the 4.1 come from? – MandoMando Nov 23 '09 at 20:13
The minimum number of sectors is 8401, so the correct minimum byte count (sector size = 512 bytes) is actually 4,301,312. That gives 4.10205078125 MiB. – monkey_05_06 Feb 2 at 18:15

4.1 MiB is correct, however you could go smaller with FAT12, which is still readable by modern OS's.

share|improve this answer
I would, though I hear implementing a FAT12 driver is not easy. – MandoMando Nov 23 '09 at 20:14

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.