diff --git a/src/utils/datetime.ts b/src/utils/datetime.ts
index f69acad4..b2a4a434 100644
--- a/src/utils/datetime.ts
+++ b/src/utils/datetime.ts
@@ -16,18 +16,7 @@ export function dateFormatJS(opts: {
   monthStyle?: 'numeric' | '2-digit' | 'long' | 'short';
   timeStyle?: 'full' | 'long' | 'medium' | 'short';
 }) {
-  const dateObject = opts.date ? new Date(opts.date) : new Date();
-
-  const dateFormat = new Date(
-    Date.UTC(
-      dateObject.getUTCFullYear(),
-      dateObject.getUTCMonth(),
-      dateObject.getUTCDate(),
-      dateObject.getUTCHours(),
-      dateObject.getUTCMinutes(),
-      dateObject.getUTCSeconds(),
-    ),
-  );
+  const dt = opts.date ? new Date(opts.date) : new Date();
 
   const { locale } = i18n.global;
 
@@ -35,20 +24,21 @@ export function dateFormatJS(opts: {
     opts.locale = locale.value === Lang.Thai ? 'th-Th' : 'en-US';
   }
 
-  let formattedDate = new Intl.DateTimeFormat(opts.locale, {
+  let formatted = new Intl.DateTimeFormat(opts.locale, {
     day: opts.dayStyle || 'numeric',
     month: opts.monthStyle || 'short',
     timeStyle: opts.timeStyle,
     year: 'numeric',
-  }).format(dateFormat);
+  }).format(dt);
 
-  if (opts.locale === 'th-Th') {
-    formattedDate = formattedDate.replace(/(\d{4})/, (year) =>
-      (parseInt(year) - 543).toString(),
-    );
+  switch (opts.locale) {
+    case 'th-Th':
+      return formatted.replace(/(\d{4})/, (year) =>
+        (parseInt(year) - 543).toString(),
+      );
+    default:
+      return formatted;
   }
-
-  return formattedDate;
 }
 
 /**
@@ -67,10 +57,7 @@ export function dateFormat(
   if (!m.isValid()) return '';
 
   if (time) return m.format('HH:mm');
-  if (number) {
-    const formattedNumberDate = m.format('L');
-    return formattedNumberDate;
-  }
+  if (number) return m.format('L');
 
   const monthFormat = fullmonth ? 'MMMM' : 'MMM';
   const formattedDate = m.format(
@@ -107,25 +94,22 @@ export function toISOStringWithTimezone(date: Date) {
   );
 }
 
-export function calculateAge(birthDate: Date | null | string): string;
+export function calculateAge(dt: Date | null | string): string;
 export function calculateAge(
-  birthDate: Date | null | string,
+  dt: Date | null | string,
   only: 'year' | 'months' | 'days',
 ): number;
 export function calculateAge(
-  birthDate: Date | null | string,
+  dt: Date | null | string,
   only?: 'year' | 'months' | 'days',
 ) {
-  if (!birthDate) return null;
+  if (!dt) return null;
 
-  const birthDateTimeStamp = new Date(birthDate).getTime();
-  const now = new Date();
-  const diff = now.getTime() - birthDateTimeStamp;
-
-  const ageDate = new Date(diff);
-  const years = ageDate.getUTCFullYear() - 1970;
-  const months = ageDate.getUTCMonth();
-  const days = ageDate.getUTCDate() - 1;
+  const diff = Date.now() - new Date(dt).getTime();
+  const offset = new Date(diff);
+  const years = offset.getUTCFullYear() - 1970;
+  const months = offset.getUTCMonth();
+  const days = offset.getUTCDate() - 1;
 
   switch (only) {
     case 'year':