diff --git a/nsencoder.go b/nsencoder.go
index 692e1a6..48e3c72 100644
--- a/nsencoder.go
+++ b/nsencoder.go
@@ -127,15 +127,25 @@ func appendNumber(result *[]string, number string, useHex bool, groupSize int) {
 		maxValue = intMaxValue(useHex, maxDigits)
 	}
 
+	// Check if the number exceeds the maximum value
 	if num > maxValue {
 		fmt.Fprintf(os.Stderr, "Warning: Number %d is too large for group size %d. Using maximum value %d.\n", num, groupSize, maxValue)
 		num = maxValue
 	}
 
+	// Calculate the required length of the number based on the group size
+	requiredLength := groupSize
 	if useHex {
-		formatted = fmt.Sprintf("0x%X", num)
+		requiredLength -= 2 // For "0x" prefix
 	} else {
-		formatted = fmt.Sprintf("0d%d", num)
+		requiredLength -= 2 // For "0d" prefix
+	}
+
+	// Format the number with padding
+	if useHex {
+		formatted = fmt.Sprintf("0x%0*X", requiredLength, num)
+	} else {
+		formatted = fmt.Sprintf("0d%0*d", requiredLength, num)
 	}
 
 	*result = append(*result, formatted)