DPI Wizard

All these parts are correct.

The calculator suggest the lowest possible DPI based on the sensitivity range of the game, as in the first link where it suggests 1440 DPI. But the calculator doesn't know you have the possibility to configure 1440, so it can't just assume you are using it. Some users might have to go to 1400 DPI, others 1000 DPI etc depending on the driver and supported DPI resolution. The DPI used for the calculation is the one entered, there is no way around this without causing a ton of confusion.
 
The multiplier is based on the entered DPI. If the entered DPI is causing the sensitivity to be out of range, the only solution as it is right now is to suggest a DPI that causes the sensitivity to fall within a valid range. Technically it could also suggest a multiplier, but there's no way to enter a DPI multiplier into the calculator, you need to enter the effective DPI.
For this to work the way I think you want we would need a new DPI multiplier field, but I'm a bit reluctant to add more fields to the calculator covering rare edge cases, as it mostly causes confusion.

Hey! Answer is here  It is always shown for ADS and scopes in advanced mode.
And the original suggestion is here, but it doesn't contain any math regarding how it's calculated.

There's a link on the front page about what it is. It's for reverse calculating your existing sensitivity to find the correct (or closest) conversion method.
It's not linked to the swap button between the games, this button swaps the output game for the input game. Although this swap button is somewhat confusingly also labelled as reverse in some cases, it will be re-labelled swap in the up upcoming updates.

Which weapon are you using in Crossfire? I've added a few snipers now, but the sensitivity relative to your conversion is about the same.
Also, how is the sensitivity too slow? Are you expecting the same 360 distance for the zoom in crossfire as in CS2?

This required some thinking since the vertical sensitivity can be different than the horizontal for the closest match, but I managed to figure it out! Coming in the next update:

I just tested all the scopes, and everything is spot on. If the calculation is out of range there's not much you can do other than try to tweak the base mouse sensitivity, but that has a limited impact.

I've updated the FOV Notes to include a link to a working FOV changer, use this to avoid any confusion

Set Building and Edit sensitivity to 100% to keep them the same as hipfire.

I've added the option to adjust the coefficient for Jedi's Trick now.

The game needed an update, so check again now. Your 8x will be out of range though, due to limitations in the game.

You have done it right. There's a quite big difference in the FOV between the games, so the Handgun Iron Sight / Reflex in MW is about the same FOV as hipfire in Fortnite. Not much you can do about this though, but it might make the relation between hipfire and aims feel a bit weird in Fortnite.

Since there is a mismatch between horizontal and vertical FOV because of the stretching, it depends on which axis you want to preserve. If they feel too fast with MDH 100%, switch to MDV 177.7778% instead.

You have done it correctly, although you should technically use MDV 178% and not 177.7778% to match Relative Coefficient 1.78, but this will not make a discernible difference.
That is what you should put in the config file yes, and for scalar 0 you have to choose between the two options depending on what you prefer.

As said above, the calculator already does "everything" for you, you don't need to know anything about the complexities of the math, you only need to specify how you want the sensitivity to be converted.
While it could be possible to to make AI answer questions such as
"What sensitivity do I need to set in-game in RoboCop: Rogue City with FOV 116, resolution 2560x1440 and 800 DPI to match the 360 distance of in-game sensitivity 1.48 Apex Legends with FOV 110, 3440x1440 and 1000 DPI?"
it would be faster and more reliable to just select these options in the calculator.

It's the "Viewspeed - Vertical" option.

Set the FOV in Aimlabs to the same FOV as you ADS in siege, then match the 360 distance. This will make it identical.

Since Legacy MW is based on a specific FOV, you have to use this FOV as the source for your conversion. So do like this, and just change the game you are converting to.

The vertical FOV is the same with 4:3 stretched and 16:9, so you need to switch the conversion to MDH 100% instead of MDV 133%:
https://www.mouse-sensitivity.com/?share=1083d3cd8f5b3a3010a2dd484aba6bdd
That should feel better.

I do agree that this would be a good thing to have in place, I will try to get it up and also integrated as soon as I can.

The in-game sensitivity has a quite limited range, if you use the config file instead you should be able to match it without changing DPI.

The recoil, and any other forced movement like sway and head bob, are based on set parameters that move you x degrees up, down, left and right. It is completely detached from your sensitivity setting. If that is what you were asking  

This is not related to the discrepancy shown by the calculator. This discrepancy shows you what the sensitivity/360 distance is with the calculated sensitivity is compared to the target sensitivity/360 distance, and is caused by the lack of decimal support by the game.
The inaccurate slider note means that when you set the slider to say 3.3 it might in reality be anything from for example 3.21 to 3.39. This is the case for a lot of games unfortunately, and if there's no config file option there's not much you can do about it.
This will make the actual sensitivity differ from the calculation, but usually not by a significant amount. Although this will vary depending on your sensitivity. If your target sensitivity is for instance 0.2, and the actual sensitivity is 0.29 due to the slider being inaccurate, you will get a significant difference since it's 1.45 times higher.
 

My bad, I thought they had moved everything to the GameUserSettings.ini file. I've fixed and updated everything now

Since Fortnite is 3rd person and has a quite narrow FOV, it's really hard to make it "feel" the same as a 1st person game with a wider FOV.
What you have tried is the correct way to go about it, but I would suggest also trying 133 and 178%.