diff --git a/gui/itemStats.py b/gui/itemStats.py
index db1b8303f..bbee1b12b 100644
--- a/gui/itemStats.py
+++ b/gui/itemStats.py
@@ -321,7 +321,7 @@ class ItemParams (wx.Panel):
 
         trans = {"Inverse Absolute Percent": (lambda: (1-value)*100, unitName),
                  "Inversed Modifier Percent": (lambda: (1-value) * 100, unitName),
-                 "Modifier Percent": (lambda: (1-value) * 100, unitName),
+                 "Modifier Percent": (lambda: (value-1) * 100, unitName),
                  "Volume": (lambda: value, u"m\u00B3"),
                  "Sizeclass": (lambda: value, ""),
                  "Absolute Percent": (lambda: (value * 100) , unitName),