diff --git a/core/growable/growable.factor b/core/growable/growable.factor
index fc981d643c..09189991f7 100644
--- a/core/growable/growable.factor
+++ b/core/growable/growable.factor
@@ -46,7 +46,7 @@ M: growable set-length ( n seq -- )
     ] if
     length<< ;
 
-: new-size ( old -- new ) 1 + 3 * ; inline
+: new-size ( old -- new ) 1 + 2 * ; inline
 
 : ensure ( n seq -- n seq )
     bounds-check-head