diff --git a/PROMS/Volian.Utils.Library/CvtFont/CvtFont.cs b/PROMS/Volian.Utils.Library/CvtFont/CvtFont.cs
index 4d6018d4..56ece2e2 100644
--- a/PROMS/Volian.Utils.Library/CvtFont/CvtFont.cs
+++ b/PROMS/Volian.Utils.Library/CvtFont/CvtFont.cs
@@ -282,7 +282,10 @@ namespace CvtFont
 		public static float GetCPIs(uint i)
 		{
 			if (FontIsPropt(i))	return 12;
-			return CPIS[i & 63];
+			uint j = i & 63;
+			if (j > CPIS.Length - 1)
+				return CPIS[0];
+			return CPIS[j];
 		}
 		public static float GetPrintPitch(uint i)
 		{