diff --git a/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs b/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs
index 2894c2159..b972394a4 100644
--- a/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs
+++ b/Plugins/Flow.Launcher.Plugin.Calculator/Main.cs
@@ -24,7 +24,7 @@ namespace Flow.Launcher.Plugin.Calculator
                         @"[ei]|[0-9]|0x[\da-fA-F]+|[\+\%\-\*\/\^\., ""]|[\(\)\|\!\[\]]" +
                         @")+$", RegexOptions.Compiled);
         private static readonly Regex RegBrackets = new Regex(@"[\(\)\[\]]", RegexOptions.Compiled);
-        private static readonly Regex ThousandGroupRegex = new Regex(@"\B(?=(\d{3})+(?!\d))");
+        private static readonly Regex ThousandGroupRegex = new Regex(@"\B(?=(\d{3})+(?!\d))", RegexOptions.Compiled);
         private static readonly Regex NumberRegex = new Regex(@"[\d\.,]+", RegexOptions.Compiled);
 
         private static Engine MagesEngine;