diff --git a/pick/__main__.py b/pick/__main__.py
index 9f2d535..6778f87 100644
--- a/pick/__main__.py
+++ b/pick/__main__.py
@@ -1343,7 +1343,7 @@ def magnifier_clicked(self, window, ev):
 
     def get_colour_from_pb(self, pb):
         pixel_data = pb.get_pixels()
-        offset = (pb.get_rowstride() * (self.snapsize[1] / 2)) + ((self.latest_pb.get_rowstride() / self.snapsize[0]) * (self.snapsize[0] / 2))
+        offset = pb.get_rowstride() * pb.get_height() / 2 + (pb.get_rowstride() / 2)
         rgb_vals = tuple([ord(x) for x in pixel_data[offset:offset+3]])
         return rgb_vals