diff --git a/programmers/콜라츠 추측/solution.java b/programmers/콜라츠 추측/solution.java
new file mode 100644
index 0000000..2464f2d
--- /dev/null
+++ b/programmers/콜라츠 추측/solution.java	
@@ -0,0 +1,20 @@
+// [문제 링크]: https://school.programmers.co.kr/learn/courses/30/lessons/12943
+
+class Solution {
+    public int solution(long num) {
+        int answer = 0;
+        for(int i = 0; i < 501; i++){
+            if(num == 1){
+                answer = i;
+                break;
+            }
+            if(i== 500) {
+                answer = -1;
+                break;
+            }
+            if(num%2==0) num /= 2;
+            else num = 3 * num + 1;
+        }
+        return answer;
+    }
+}
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