diff --git a/website/docs/language/functions/substr.mdx b/website/docs/language/functions/substr.mdx
index dab4e3a8f92b..8317848de791 100644
--- a/website/docs/language/functions/substr.mdx
+++ b/website/docs/language/functions/substr.mdx
@@ -7,7 +7,7 @@ description: |-
 
 # `substr` Function
 
-`substr` extracts a substring from a given string by offset and length.
+`substr` extracts a substring from a given string by offset and (maximum) length.
 
 ```hcl
 substr(string, offset, length)
@@ -36,3 +36,11 @@ string after the given offset will be returned.
 > substr("hello world", -5, -1)
 world
 ```
+
+If the length is greater than the length of the string, the substring
+will be the length of all remaining characters.
+
+```
+> substr("hello world", 6, 10)
+world
+```