diff --git a/BizHawk.Util/InputValidate.cs b/BizHawk.Util/InputValidate.cs
index 071c436a5c..01bd3613fa 100644
--- a/BizHawk.Util/InputValidate.cs
+++ b/BizHawk.Util/InputValidate.cs
@@ -259,8 +259,14 @@ namespace BizHawk
 
 		public static bool IsValidDecimalNumber(char c)
 		{
-			if (c < 48 || c > 58) //45 = dash, 46 = dot
+			if (c == 45 || c == 46) //45 = dash, 46 = dot
+			{
+				return true;
+			}
+			else if (c < 48 || c > 58)
+			{
 				return false;
+			}
 
 			return true;
 		}