diff --git a/src/main/java/com/packt/datastructuresandalg/lesson1/activity/octaltodecimal/OctalToDecimal.java b/src/main/java/com/packt/datastructuresandalg/lesson1/activity/octaltodecimal/OctalToDecimal.java
index e04b605..b5a8f92 100644
--- a/src/main/java/com/packt/datastructuresandalg/lesson1/activity/octaltodecimal/OctalToDecimal.java
+++ b/src/main/java/com/packt/datastructuresandalg/lesson1/activity/octaltodecimal/OctalToDecimal.java
@@ -2,6 +2,20 @@
 
 public class OctalToDecimal {
     public int convertToDecimal(String octal) {
-        return 999;
+        /*
+		 * Given: 75532
+		 * formula => 2*8^0 + 3*8^1
+		 */
+		// the result to be displayed
+		int output = 0;
+		// the length of the input string
+		int len = octal.length();
+		
+		for(int i = len-1; i >= 0; i--) {
+			// the value of the char in integer
+			int num = Integer.parseInt(octal.valueOf(octal.charAt(i)));
+			output += (num * (int) Math.pow(8, (len-1)-i));
+		}
+		return output;
     }
 }