diff --git a/common/lib/calc/calc/preview.py b/common/lib/calc/calc/preview.py
index 3f0e745c59..075a134303 100644
--- a/common/lib/calc/calc/preview.py
+++ b/common/lib/calc/calc/preview.py
@@ -119,6 +119,9 @@ def enrich_varname(varname):
     # add hbar for QM
     greek.append('hbar')
 
+    # add infinity
+    greek.append('infty')
+
     if varname in greek:
         return ur"\{letter}".format(letter=varname)
     else: