diff --git a/desmos.md b/desmos.md
index 60fa154..d81a3e8 100644
--- a/desmos.md
+++ b/desmos.md
@@ -63,7 +63,7 @@ trying to compute abs(x) by polynomials, or something. weird stuff.
 
 ### [doom turnspeeds](https://www.desmos.com/calculator/zfscpmsdbk)
 
-i used this to help design turnspeed smoothing in [my zdoom patch.](https://eaguru.guru/t/zdoom_smoothstep.patch)
+i used this to help design turnspeed smoothing in [my zdoom patch.](https://eaguru.guru/t/zdoom_smoothstep.diff)
 
 *note to self: i think i have a more recent version of that patch lying around somewhere.*