What is mouse sensitivity and the difference between DPI & eDPI

Mouse DPI (Dots Per Inch) is a hot topic among gamers as many are searching for the best mouse DPI settings for numerous FPS games. Still, this is fundamentally wrong as it only covers one part of the story. The important thing they should be looking for is the in-game mouse sensitivity also referred to as effective Dots Per Inch (eDPI).

In this article I’ll dive deeper into this topic, what DPI actually is, the misconception around it, and the relation between DPI and screen resolution. 

Furthermore, what eDPI is and the basics on how to synchronize this between 2 different games having the same in-game mouse sensitivity as a result. So, without any further ado, let’s dive right into it.

What is mouse DPI (Dots Per Inch)?

I’ll start with an example, imagine your mousepad is divided into 1 by 1-inch segments as shown below. Each segment is divided into a grid. Your mouse DPI settings determine how fine this grid is. If you assign the settings to 800, this means that each segment is divided into an 800 by 800 grid, each intersection represents a dot.  In the case of 800 DPI, the dots are 0.03175mm separated from each other.

When you move your mouse, the sensor jumps from one dot to another depending on the direction of mouse movement, this is referred to as a “count” The higher the mouse DPI settings are, the denser the senor grid will be and the more screen space your cursor will cover when moving your mouse 1 inch = the higher your sensitivity will be.

When represented like this you might conclude that the denser the senor grid is the more accurate your mouse movement is processed, and you would be right if this was the full picture, but it isn’t as we haven’t taken screen resolution into account.

The relation between mouse DPI and screen resolution.

Every screen has a certain pixel resolution like 1920*1080 for example. This means that there are 1920 pixels in the width of the screen and 1080 in the height which gives a total of
2.073 million px.

What I need to know to prove my point is the pixel density or pixels per inch (PPI), therefore I need to know the screen size, for example, 24 inch. In that case, the PPI is 91.79px with a pixel size of 0.276mm, this is also the smallest amount you can move your cursor on the screen as it represents the size of 1 pixel.
If we compare this with our DPI density of 0.03175mm we can conclude that it is no use to increase our DPI in order to increase our cursor accuracy because the DPI grid density is already x8.7 times higher than the pixel density of our screen representing the minimum amount of visible cursor movement. You can state that the pixel/count ratio = 0.1147 In order to have mouse skipping, which is moving your mouse 1 count without visibly moving your screen cursor 1 pixel your DPI should be below 90 DPI having a pixel/count ratio above 1.

Note that this is only true for 2D desktop movement as we haven’t taken the in-game sensitivity and FOV value into account.

eDPI / 360° Spin distance

The reason why eDPI is the better method to determinate mouse sensitivity compared to DPI alone is that it takes your in-game sensitivity also into account making it possible to synchronize this across different games, meaning that your 360°-character spin distance is always the same no matter the game. This is not the case when just synchronizing your mouse DPI settings, making it in fact useless to do.

But since there is no standard when it comes to in-game sensitivity values and since most games are applying different methods to calculate the sensitivity effect resulting in a different outcome, it is nearly impossible to figure this out on your own, and that’s when a sensitivity calculator comes in handy. The most famous one and by far the best is www.mousesensitivity.com, some of its features are behind a paywall so not everything is free, but the feature you need to determine your eDPI is 360° distance which is free for all games.

Below I’ve added a practical example for converting Overwatch to Apex Legends.
All you need to do is select Overwatch from the drop-down and fill in your in-game sensitivity for Overwatch, which in this case is 6.1 same goes for mouse DPI settings which are 800 for this example. (highlighted in blue)

From the “Convert to” tab (highlighted in red) simply select the game you want to convert to, so for this example Apex Legends and the result will be shown immediately below (highlighted in the green).

The 2 values that you need to look for are the sensitivity which is 1.83000 for Apex and the 360° distance which is 11.1773 inch which is the same for both games resulting in the same 360° spin distance. 

The eDPI for this case is 800 (DPI) / 11.1773 (360° Distance) = 71.57 eDPI.

But it’s a lot more convenient to just refer to the 360° spin distance which is basically the same as both parameters, DPI and In-game sensitivity are taken into account.

As a result, your in-game mouse sensitivity (eDPI) is synchronized between the 2 games as you just need to put in 1.83 as sensitivity value for Apex Legends and you are done!

I hope you find this quick guide about Mouse DPI settings useful,  in the next article I’ll take an in-depth look into the mouse synchronization part, taking FOV into account and why it’s important. I might even share a secret to cut your warmup time in half and make you overall a more consistent aimer just by adjusting your DPI in a very special way!

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