diff --git a/apps/main/src/utils/getAge.test.ts b/apps/main/src/utils/getAge.test.ts
index 92a7c3a..9b98459 100644
--- a/apps/main/src/utils/getAge.test.ts
+++ b/apps/main/src/utils/getAge.test.ts
@@ -1,7 +1,6 @@
 import { testing } from "./getAge"
 
-const { birth, dateFormatOption, getAge, ageInt, ageDecimal, isOverBirthDay } =
-    testing
+const { birth, getAge, ageInt, ageDecimal, isOverBirthDay } = testing
 
 describe("getAge tests", () => {
     test("birthday to be 2002-07-30", () => {
@@ -73,15 +72,6 @@ describe("getAge tests", () => {
         expect(isOverBirthDay(date)).toEqual(testData.overBD)
     })
 
-    test("dateFormatOption to work properly", () => {
-        expect(
-            new Date("2002-07-30, 00:00:00.000 +09:00").toLocaleString(
-                "en-US",
-                dateFormatOption
-            )
-        ).toEqual("7/30/2002, 00:00:00.000 GMT+09:00")
-    })
-
     test("ageInt to work", () => {
         expect(ageInt(birth)).toEqual(0)
         expect(ageInt(new Date("2023-07-29"))).toEqual(20)
diff --git a/apps/main/src/utils/getAge.ts b/apps/main/src/utils/getAge.ts
index 2eb84b8..9ddebc6 100644
--- a/apps/main/src/utils/getAge.ts
+++ b/apps/main/src/utils/getAge.ts
@@ -1,32 +1,12 @@
-const dateFormatOption: Intl.DateTimeFormatOptions = {
-    timeZone: "Asia/Seoul",
-    timeZoneName: "longOffset",
-    hourCycle: "h23",
-    year: "numeric",
-    month: "numeric",
-    day: "numeric",
-    hour: "numeric",
-    minute: "numeric",
-    second: "numeric",
-    fractionalSecondDigits: 3,
-}
-
 // my birthday in KST :D
-const birth = new Date(
-    new Date("2002-07-30, 00:00:00.000 +09:00").toLocaleString(
-        "en-US",
-        dateFormatOption
-    )
-)
+const birth = new Date("2002-07-30, 00:00:00.000 +09:00")
 
 /**
  * Gets developomp's age with decimal precision
  *
  * @param now - current `Date` in KST
  */
-export default function getAge(
-    now: Date = new Date(new Date().toLocaleString("en-US", dateFormatOption))
-): number {
+export default function getAge(now: Date = new Date()): number {
     return ageInt(now) + ageDecimal(now)
 }
 
@@ -76,7 +56,6 @@ function isOverBirthDay(now: Date): boolean {
 
 export const testing = {
     birth,
-    dateFormatOption,
     getAge,
     ageInt,
     ageDecimal,