diff --git a/readme.md b/readme.md
index f171759..6d123af 100644
--- a/readme.md
+++ b/readme.md
@@ -108,7 +108,7 @@ device-specific.)
 
 The program's caching behavior can be controlled in the Options menu. By default, all caching is OFF.
 
-The program can optionally output Graph/Data files in .GraphML format (.graphml) for data portability. This can be 
+The program can optionally output Graph/Data files in GraphML format (.graphml) for data portability. This can be 
 turned on in the Options menu. By default, GraphML output is OFF.
 
 ---