diff --git a/src/interfaces/extension.ts b/src/interfaces/extension.ts
index 24da5b93..836c994d 100644
--- a/src/interfaces/extension.ts
+++ b/src/interfaces/extension.ts
@@ -252,10 +252,7 @@ class Extension {
   public static CheckCitizen(value: string) {
     let citizen = value;
     if (citizen == null || citizen == "" || citizen == undefined) {
-      throw new HttpError(
-        HttpStatus.NOT_FOUND,
-        "กรุณากรอกข้อมูลรหัสบัตรประจำตัวประชาชน",
-      );
+      throw new HttpError(HttpStatus.NOT_FOUND, "กรุณากรอกข้อมูลรหัสบัตรประจำตัวประชาชน");
     }
     if (citizen.length !== 13) {
       throw new HttpError(
@@ -281,10 +278,7 @@ class Extension {
     const chkDigit = (11 - calStp2) % 10;
 
     if (citizenIdDigits[12] !== chkDigit) {
-      throw new HttpError(
-        HttpStatus.NOT_FOUND, 
-        "ข้อมูลรหัสบัตรประจำตัวประชาชนไม่ถูกต้อง"
-      );
+      throw new HttpError(HttpStatus.NOT_FOUND, "ข้อมูลรหัสบัตรประจำตัวประชาชนไม่ถูกต้อง");
     }
     return citizen;
   }
@@ -295,6 +289,8 @@ class Extension {
     subtractYear: number = 0,
   ): number {
     if (appointDate == null || appointDate == undefined) return 0;
+    // Check for Invalid Date
+    if (isNaN(appointDate.getTime())) return 0;
     const now = new Date();
     if (now.getMonth() - appointDate.getMonth() >= 6) {
       return now.getFullYear() - appointDate.getFullYear() + 1 + plusYear - subtractYear;
@@ -312,13 +308,20 @@ class Extension {
     return years;
   }
 
-  public static CalculateAgeStrV2(date: Date, plusYear: number = 0, subtractYear: number = 0, method?:string) {
+  public static CalculateAgeStrV2(
+    date: Date,
+    plusYear: number = 0,
+    subtractYear: number = 0,
+    method?: string,
+  ) {
     if (date == null || date == undefined) return "";
+    // Check for Invalid Date
+    if (isNaN(date.getTime())) return "";
     const currentDate = new Date();
     if (date > currentDate && method !== "GET") {
       throw new Error("วันเกิดต้องไม่มากกว่าวันที่ปัจจุบัน");
-    }else if(date > currentDate && method === "GET"){
-      return ""
+    } else if (date > currentDate && method === "GET") {
+      return "";
     }
 
     let years = currentDate.getFullYear() - date.getFullYear();
@@ -388,9 +391,13 @@ class Extension {
   }
 
   public static toDateOnlyString(date: Date): string {
-    return date.getFullYear() + "-" +
-        String(date.getMonth() + 1).padStart(2, "0") + "-" +
-        String(date.getDate()).padStart(2, "0");
+    return (
+      date.getFullYear() +
+      "-" +
+      String(date.getMonth() + 1).padStart(2, "0") +
+      "-" +
+      String(date.getDate()).padStart(2, "0")
+    );
   }
 }