Fans Dimensions Confusion.


Jan 6, 2008
What does it mean if one fan has dimension 230x220x25?

BTW shouldnt the first 2 dimensions be the same? Like 230x230xYY? Cause i know that 230 is the fans diameter right? and will 25 make it the depth?

Also how does it differ if fans depth is 25 vs 38? 38's seem to be used as Cpu fans will 25 for the case, why might that be?


Nov 20, 2007
There are fans from 25mm square, 8mm thick.

A standard 120mm square fan from the same manufacturer at 25mm thick will have less pressure and CFM than one 38mm thick as long as the RPM is the same. The blade design/thickness would change of course.

If I saw a 220x230mm fan dimension I'd say it's a typo error.

A link to show how involved fan testing is.
I agree with Conumdrum that it is probably a typo. The 25 is the thickness. Most fans are 25mm thick. The 38mm ones move more air, but may not fit, so measure.
Indicentally, I just installed a Scythe Ultra-KAZE 38mm fan into my RC-690, and I haven't reached a verdict on it yet. It is super-quiet, but does not move a lot of air. It's supposed to spin at 1000rpm, but Abit uguru has it pegged at 660 no matter what voltage in the range of 8.5v-12v I'm feeding it. I can barely feel the air; it won't "float" a piece of paper put over it. I'm going to use its adapter and plug straight to my PSU, but the mobo header was working, as this fan was a replacement for another that was getting noisy.

Hey Guys! It is not a typo. There are case fans 200mm and above that have elliptical "frames" or rectangular "frames" instead of square ones. Another way to put it is that the "frames" on two opposite sides are thinner. They are made that way so that they can fit inside a pc case. Some of the larger CoolerMaster case fans are like that.

EDIT - Here's an example of Antec and CoolerMaster "odd shaped" fans: