diff --git a/TBF/Boxes/DoubleBox.cs b/TBF/Boxes/DoubleBox.cs
index f90508298..6cc20a0e7 100644
--- a/TBF/Boxes/DoubleBox.cs
+++ b/TBF/Boxes/DoubleBox.cs
@@ -76,7 +76,7 @@ namespace TBF.Boxes
 			}
 			else
 			{
-                return string.Format( $"{{0:{Format}}}", Val * Factor);
+                return string.Format(string.Format("{{0:{0}}}", Format), Val * Factor);
 			}
         }