diff --git a/DATFromDir/DATFromDir.cs b/DATFromDir/DATFromDir.cs
index 1a7f6b3d..ca15d71e 100644
--- a/DATFromDir/DATFromDir.cs
+++ b/DATFromDir/DATFromDir.cs
@@ -492,9 +492,9 @@ namespace SabreTools
 				long extractedsize = Convert.ToInt64(gzsize, 16);
 
 				// Only try to add if the file size is greater than 2.5 GiB
-				if (filesize >= (2.5 * 1024 * 1024 * 1024))
+				if (filesize >= (2.5 * Constants.GibiByte))
 				{
-					// ISIZE is mod 2^32, so we add that if the ISIZE is smaller than the filesize and header
+					// ISIZE is mod 4GiB, so we add that if the ISIZE is smaller than the filesize and header
 					if (extractedsize < (filesize - neededHeaderSize))
 					{
 						_logger.Log("Filename: '" + Path.GetFullPath(item) + "'\nExtracted file size: " +
@@ -502,7 +502,7 @@ namespace SabreTools
 					}
 					while (extractedsize < (filesize - neededHeaderSize))
 					{
-						extractedsize += (long)Math.Pow(2, 32);
+						extractedsize += (4 * Constants.GibiByte);
 					}
 					_logger.Log("Final file size: " + extractedsize + "\nExtracted CRC: " + gzcrc +
 						"\nExtracted MD5: " + gzmd5 + "\nSHA-1: " + Path.GetFileNameWithoutExtension(item));
diff --git a/SabreHelper/Data/Constants.cs b/SabreHelper/Data/Constants.cs
index 4d5a4176..81a6bb20 100644
--- a/SabreHelper/Data/Constants.cs
+++ b/SabreHelper/Data/Constants.cs
@@ -1,4 +1,6 @@
-namespace SabreTools.Helper
+using System;
+
+namespace SabreTools.Helper
 {
 	public class Constants
 	{
@@ -47,5 +49,19 @@
 		public static string HeaderPatternCMP = @"(^.*?) \($";
 		public static string ItemPatternCMP = @"^\s*(\S*?) (.*)";
 		public static string EndPatternCMP = @"^\s*\)\s*$";
+
+		// Byte (1024-based) size comparisons
+		public static long KibiByte = 1024;
+		public static long MibiByte = (long)Math.Pow(KibiByte, 2);
+		public static long GibiByte = (long)Math.Pow(KibiByte, 3);
+		public static long TibiByte = (long)Math.Pow(KibiByte, 4);
+		public static long PibiByte = (long)Math.Pow(KibiByte, 5);
+
+		// Byte (1000-based) size comparisons
+		public static long KiloByte = 1000;
+		public static long MegaByte = (long)Math.Pow(KiloByte, 2);
+		public static long GigaByte = (long)Math.Pow(KiloByte, 2);
+		public static long TeraByte = (long)Math.Pow(KiloByte, 2);
+		public static long PetaByte = (long)Math.Pow(KiloByte, 2);
 	}
 }