Ok. Time to ask a stupid question. How in Gods green earth do you measure a PC case fan. Iv heard diagonally, down the middle, screw hole to screw hole, edge to edge. I want a definitive answer. How to you measure a PC case fan. PC that needs the fan in case that helps: gateway dx4870-ub318
Ok. Im having to measure the fan by using the case. I measured from hole to hole and got 85mm and 70mm. ( i can mount 2 diffferent size fans) I cant measure a fan due to the fact of not having one. I know a 120 is too big and a 80mm is to small. So is a 92mm what i need?
The size of fan you need will generally be determined by the size of the fan fitting position in your PC case. The sizes of all the fans on our website are shown as measured along any one of the fan's four sides, NOT the distance between the fan's screw holes! Our most popular fan size is 120mm, followed by 80mm. This isn't really dictated by customer preference, but more by recent designs of PC cases.
As for the thickness (depth) of the fan, generally 25mm (1 inch) is by far the most common depth, although smaller fans can have shallower depths such as 15mm or even 10mm. All our fans are 25mm thick unless otherwise stated. If you have any questions about which fan you should order, please don't hesitate to get in touch.
If you know the distance between the fan mounting screw holes but don't know what fan size to order, please see the following table. Note that the mounting hole measurements shown below are taken horizontally or vertically between the holes and not diagonally.
Screw hole spacings and fan sizes
32mm between screw holes 40mm fan size
40mm between screw holes 50mm fan size
50mm between screw holes 60mm fan size
60mm between screw holes 70mm fan size
72mm between screw holes 80mm fan size
83mm between screw holes 92mm fan size
105mm between screw holes 120mm fan size