In the game you find the setting under Options → Controls → General → Sensitivity.
Conversion
Fortnite to Overwatch 2 Sensitivity
In short: Fortnite sens times 0.8418. 6% becomes 5.05. For your own value, just edit the sentence below.
How to set it in Overwatch 2
What changes when you go from Fortnite to Overwatch 2
Overwatch 2 turns 1.19 times further per mouse count than Fortnite. That is why the number gets smaller while your mouse distance stays the same.
Overwatch 2 shows 23° more field of view than Fortnite by default (103° against 80°). The picture looks a little wider and movement on screen a little slower.
In Overwatch 2 you can enter up to 2 decimal places. Use all of them to keep the conversion exact.
Common questions
How do I convert Fortnite sens to Overwatch 2?
Multiply your Fortnite sens by 0.8418. 6% in Fortnite becomes 5.05 in Overwatch 2.
Where do I set the sens in Overwatch 2?
Options → Controls → General → Sensitivity.
Why does Overwatch 2 still feel a bit different?
Fortnite: Default 80°, check in the game whether you changed it. Overwatch 2: Slider from 80° to 103°. Match the field of view as closely as you can; then the converted sens feels most natural.
Does this also apply to scopes?
No. The values are for hipfire. Zoom and scope sensitivities are set separately in the game.
Should I change my DPI?
No. Keep your DPI and only change the sens in the game. That keeps your feel the same everywhere.