diff --git a/docs/_pages/library.md b/docs/_pages/library.md
index eec4afb7..72aa6d15 100644
--- a/docs/_pages/library.md
+++ b/docs/_pages/library.md
@@ -761,7 +761,7 @@ function os.difftime(a: number, b: number): number
 
 Calculates the difference in seconds between `a` and `b`; provided for compatibility.
 
-It is adviced not to use `os.difftime(a, b)` for new work. Please use `a - b` instead.
+It is adviced not to use `os.difftime(a, b)` for new work. Please use `b - a` instead.
 
 ```
 function os.time(t: table?): number