diff --git a/OliverBooth/Formatting/DateFormatter.cs b/OliverBooth/Formatting/DateFormatter.cs
index 8d98a3b..6109cab 100644
--- a/OliverBooth/Formatting/DateFormatter.cs
+++ b/OliverBooth/Formatting/DateFormatter.cs
@@ -27,7 +27,7 @@ public sealed class DateFormatter : IFormatter
             return false;
 
 
-        formattingInfo.Write(date.ToString(formattingInfo.Format?.ToString()));
+        formattingInfo.Write(date.ToString(formattingInfo.Format?.ToString(), CultureInfo.InvariantCulture));
         return true;
     }
 }