diff --git a/README.md b/README.md
index a85a661..61d4990 100644
--- a/README.md
+++ b/README.md
@@ -84,7 +84,8 @@ See the PDF manual at <https://lukateras.github.io/nanoid.h/man.pdf>.
 
 - static inline function `int *nanoidgen(char *buffer, size_t length)`
 
-  Fills the buffer with a Nano ID of the specified length up to 256.
+  Fills the buffer with a Nano ID of the specified length up to
+  `GETENTROPY_MAX` (256).
 
   Returns the return value of [`getentropy(3)`][].
 
diff --git a/openbsd/README.md b/openbsd/README.md
index 54acd95..c4c2b43 100644
--- a/openbsd/README.md
+++ b/openbsd/README.md
@@ -84,7 +84,8 @@ See the PDF manual at <https://lukateras.github.io/nanoid.h/openbsd/man.pdf>.
 
 - static inline function `int *nanoidgen(char *buffer, size_t length)`
 
-  Fills the buffer with a Nano ID of the specified length up to 256.
+  Fills the buffer with a Nano ID of the specified length up to
+  `GETENTROPY_MAX` (256).
 
   Returns the return value of [`getentropy(2)`][].