diff --git a/src/interfaces/calculate-retire-date.ts b/src/interfaces/calculate-retire-date.ts
new file mode 100644
index 00000000..f061fb17
--- /dev/null
+++ b/src/interfaces/calculate-retire-date.ts
@@ -0,0 +1,25 @@
+class CalculateDate {
+  birthDate: Date;
+
+  public static calculateRetireDate(birthDate: Date) {
+    let dd = birthDate.getDate();
+    let mm = birthDate.getMonth();
+    let yy = birthDate.getFullYear();
+
+    let g1 = true;
+    switch (mm) {
+      case 10:
+        if (dd >= 2) g1 = false;
+        break;
+      case 11:
+      case 12:
+        g1 = false;
+        break;
+    }
+
+    if (g1) return new Date(`${yy + 60}-09-30T00:00:00.000Z`);
+    else return new Date(`${yy + 61}-09-30T00:00:00.000Z`);
+  }
+}
+
+export default CalculateDate;