Steam launch options, explained
What a launch option is, how to set one, and why the same flag can work in one game and do nothing in the next.
What a launch option is
A launch option is text that Steam adds to a game's command line when it
starts the game. Apart from one placeholder, covered below, Steam passes that
text along untouched, and the game decides what it means. -novid
skips the intro video in a Source engine game because the Source engine looks
for it, not because Steam does anything with it.
So there is no single list of Steam launch options that works everywhere. Each engine reads its own, and many games add more of their own on top. That is why every option in this catalogue is listed against the games it applies to, and names where it was documented.
How to apply a launch option on Steam
- Open Steam and go to your Library.
- Right-click the game and choose Properties.
- On the General tab, find the Launch Options field.
- Type or paste the option (e.g.
-windowed) into the field. To use several at once, separate them with spaces (e.g.-windowed -novid). - Close Properties. Steam saves automatically, and the option applies next time you launch the game.
To remove one, reopen the same field and delete the text. Options are game-specific; an option that helps one game may do nothing (or misbehave) in another.
Worth knowing: a launch option can break a game's rendering, reset local settings, or trip anti-cheat in multiplayer. Read the description first, add one at a time, and treat anything rated above Safe as a deliberate experiment.
Flags belong to engines
Most launch options are read by the engine a game is built on, so the same
job goes by different names. Unity documents -force-d3d11 to
choose its Direct3D 11 renderer; Unreal documents -dx11. A flag
from one engine's documentation is not one the other engine promises to
read.
Where an engine has enough documented flags to fill a page, it has one, along with the games in the catalogue built on it:
%command%, Linux and Steam Deck
The placeholder is %command%. Steam replaces it with the
command that starts the game, so whatever you write before it runs first.
That is how a tool that wraps the game, or an environment variable for Proton
(the compatibility layer Steam uses to run Windows games on Linux and Steam
Deck), gets in ahead of the game. Valve's Proton documentation gives the form: set
the variable, followed by %command%.
Leave %command% out and Steam hands the same text to the game
as an ordinary flag instead, so the wrapper never runs and the variable is
never set.
Read what a flag does before you paste it
Advice about launch options tends to outrun its documentation. Every option here carries its source, and its effect line says what that source actually claims. For example: