diff --git a/README.md b/README.md
index fa788822..9610d40b 100644
--- a/README.md
+++ b/README.md
@@ -74,7 +74,7 @@ compression level".
   - `8`
   - `9` Best compression (also `zlib.Z_BEST_COMPRESSION`).
 
-The default value is `zlib.Z_DEFAULT_COMPRESSION`, or `-1`.
+The default value is `zlib.Z_DEFAULT_COMPRESSION`, or `-1`.  The actual level specified by default cab be found [here](http://www.zlib.net/manual.html).
 
 **Note** in the list above, `zlib` is from `zlib = require('zlib')`.