diff --git a/core/common/src/main/java/com/hilingual/core/common/util/DateFormatter.kt b/core/common/src/main/java/com/hilingual/core/common/util/DateFormatter.kt
new file mode 100644
index 000000000..e0a4624d5
--- /dev/null
+++ b/core/common/src/main/java/com/hilingual/core/common/util/DateFormatter.kt
@@ -0,0 +1,38 @@
+package com.hilingual.core.common.util
+
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.format.DateTimeFormatter
+import java.util.Locale
+
+object DateFormatters {
+    val KOREAN_FULL_DATE: DateTimeFormatter = DateTimeFormatter.ofPattern("M월 d일 EEEE", Locale.KOREA)
+
+    val KOREAN_SHORT_DATE: DateTimeFormatter = DateTimeFormatter.ofPattern("M월 d일", Locale.KOREA)
+
+    val ISO_DATE: DateTimeFormatter = DateTimeFormatter.ISO_LOCAL_DATE
+}
+
+/**
+ * LocalDate를 한국어 전체 날짜 형식으로 변환합니다.
+ * @return "M월 d일 EEEE" 형식의 문자열 (예: "2월 6일 목요일")
+ */
+fun LocalDate.toKoreanFullDate(): String = this.format(DateFormatters.KOREAN_FULL_DATE)
+
+fun LocalDateTime.toKoreanFullDate(): String = this.format(DateFormatters.KOREAN_FULL_DATE)
+
+/**
+ * LocalDate를 한국어 짧은 날짜 형식으로 변환합니다.
+ * @return "M월 d일" 형식의 문자열 (예: "2월 6일")
+ */
+fun LocalDate.toKoreanShortDate(): String = this.format(DateFormatters.KOREAN_SHORT_DATE)
+
+fun LocalDateTime.toKoreanShortDate(): String = this.format(DateFormatters.KOREAN_SHORT_DATE)
+
+/**
+ * LocalDate를 ISO 날짜 형식으로 변환합니다.
+ * @return "yyyy-MM-dd" 형식의 문자열 (예: "2026-02-06")
+ */
+fun LocalDate.toIsoDate(): String = this.format(DateFormatters.ISO_DATE)
+
+fun LocalDateTime.toIsoDate(): String = this.format(DateFormatters.ISO_DATE)
diff --git a/core/common/src/main/java/com/hilingual/core/common/util/FormatRelativeTime.kt b/core/common/src/main/java/com/hilingual/core/common/util/FormatRelativeTime.kt
index c74532213..981cf538f 100644
--- a/core/common/src/main/java/com/hilingual/core/common/util/FormatRelativeTime.kt
+++ b/core/common/src/main/java/com/hilingual/core/common/util/FormatRelativeTime.kt
@@ -18,8 +18,6 @@ package com.hilingual.core.common.util
 import java.time.Instant
 import java.time.LocalDateTime
 import java.time.ZoneId
-import java.time.format.DateTimeFormatter
-import java.util.Locale
 import java.util.concurrent.TimeUnit
 
 private const val ONE_MINUTE = 1L
@@ -27,8 +25,6 @@ private const val ONE_HOUR_IN_MINUTES = 60L
 private const val ONE_DAY_IN_MINUTES = 1440L
 private const val ONE_WEEK_IN_MINUTES = 10080L
 
-private val DATE_FORMATTER = DateTimeFormatter.ofPattern("M월 d일", Locale.KOREA)
-
 fun formatRelativeTime(minutesAgo: Long): String {
     return when {
         minutesAgo < ONE_MINUTE -> "방금 전"
@@ -39,7 +35,7 @@ fun formatRelativeTime(minutesAgo: Long): String {
             val pastTime = System.currentTimeMillis() - TimeUnit.MINUTES.toMillis(minutesAgo)
             val instant = Instant.ofEpochMilli(pastTime)
             val localDateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault())
-            DATE_FORMATTER.format(localDateTime)
+            localDateTime.toKoreanShortDate()
         }
     }
 }
diff --git a/data/diary/src/main/java/com/hilingual/data/diary/repositoryimpl/DiaryRepositoryImpl.kt b/data/diary/src/main/java/com/hilingual/data/diary/repositoryimpl/DiaryRepositoryImpl.kt
index 6a6a2eef0..0fef3b2dd 100644
--- a/data/diary/src/main/java/com/hilingual/data/diary/repositoryimpl/DiaryRepositoryImpl.kt
+++ b/data/diary/src/main/java/com/hilingual/data/diary/repositoryimpl/DiaryRepositoryImpl.kt
@@ -17,6 +17,7 @@ package com.hilingual.data.diary.repositoryimpl
 
 import android.net.Uri
 import com.hilingual.core.common.util.suspendRunCatching
+import com.hilingual.core.common.util.toIsoDate
 import com.hilingual.data.diary.datasource.DiaryRemoteDataSource
 import com.hilingual.data.diary.model.BookmarkResult
 import com.hilingual.data.diary.model.DiaryContentModel
@@ -29,11 +30,8 @@ import com.hilingual.data.diary.model.toModel
 import com.hilingual.data.diary.repository.DiaryRepository
 import com.hilingual.data.presigned.repository.FileUploaderRepository
 import java.time.LocalDate
-import java.time.format.DateTimeFormatter
 import javax.inject.Inject
 
-private val DATE_FORMATTER: DateTimeFormatter = DateTimeFormatter.ISO_LOCAL_DATE
-
 internal class DiaryRepositoryImpl @Inject constructor(
     private val diaryRemoteDataSource: DiaryRemoteDataSource,
     private val fileUploaderRepository: FileUploaderRepository
@@ -82,7 +80,7 @@ internal class DiaryRepositoryImpl @Inject constructor(
 
         diaryRemoteDataSource.postDiaryFeedbackCreate(
             originalText = originalText,
-            date = date.format(DATE_FORMATTER),
+            date = date.toIsoDate(),
             fileKey = fileKey
         ).data!!.toModel()
     }
diff --git a/presentation/diarywrite/src/main/java/com/hilingual/presentation/diarywrite/DiaryWriteScreen.kt b/presentation/diarywrite/src/main/java/com/hilingual/presentation/diarywrite/DiaryWriteScreen.kt
index 8a98d2077..0189e98b1 100644
--- a/presentation/diarywrite/src/main/java/com/hilingual/presentation/diarywrite/DiaryWriteScreen.kt
+++ b/presentation/diarywrite/src/main/java/com/hilingual/presentation/diarywrite/DiaryWriteScreen.kt
@@ -72,6 +72,7 @@ import com.hilingual.core.common.provider.LocalTracker
 import com.hilingual.core.common.trigger.LocalDialogTrigger
 import com.hilingual.core.common.trigger.LocalMessageController
 import com.hilingual.core.common.util.UiState
+import com.hilingual.core.common.util.toKoreanFullDate
 import com.hilingual.core.designsystem.component.button.HilingualButton
 import com.hilingual.core.designsystem.component.textfield.HilingualLongTextField
 import com.hilingual.core.designsystem.theme.HilingualTheme
@@ -99,8 +100,6 @@ import kotlinx.collections.immutable.persistentListOf
 import kotlinx.coroutines.delay
 import java.io.File
 import java.time.LocalDate
-import java.time.format.DateTimeFormatter
-import java.util.Locale
 import com.hilingual.core.designsystem.R as DesignSystemR
 
 @Composable
@@ -542,7 +541,7 @@ private fun DateText(
     val selectedDate = selectedDateProvider()
 
     val formattedDate = remember(selectedDate) {
-        selectedDate.format(DATE_FORMATTER)
+        selectedDate.toKoreanFullDate()
     }
 
     Text(
@@ -552,9 +551,6 @@ private fun DateText(
     )
 }
 
-private val DATE_FORMATTER: DateTimeFormatter =
-    DateTimeFormatter.ofPattern("M월 d일 EEEE", Locale.KOREAN)
-
 private fun createTempImageFile(context: Context): Pair<Uri, File> {
     val imageFile = File.createTempFile("camera_", ".jpg", context.cacheDir)
     val uri = FileProvider.getUriForFile(
diff --git a/presentation/home/src/main/java/com/hilingual/presentation/home/component/footer/DiaryDateInfo.kt b/presentation/home/src/main/java/com/hilingual/presentation/home/component/footer/DiaryDateInfo.kt
index b85aa0d6e..9d68663bb 100644
--- a/presentation/home/src/main/java/com/hilingual/presentation/home/component/footer/DiaryDateInfo.kt
+++ b/presentation/home/src/main/java/com/hilingual/presentation/home/component/footer/DiaryDateInfo.kt
@@ -26,13 +26,9 @@ import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.tooling.preview.PreviewParameter
 import androidx.compose.ui.tooling.preview.PreviewParameterProvider
 import androidx.compose.ui.unit.dp
+import com.hilingual.core.common.util.toKoreanFullDate
 import com.hilingual.core.designsystem.theme.HilingualTheme
 import java.time.LocalDate
-import java.time.format.DateTimeFormatter
-import java.util.Locale
-
-private val DATE_FORMATTER: DateTimeFormatter =
-    DateTimeFormatter.ofPattern("M월 d일 EEEE", Locale.KOREAN)
 
 @Composable
 internal fun DiaryDateInfo(
@@ -42,7 +38,7 @@ internal fun DiaryDateInfo(
     modifier: Modifier = Modifier
 ) {
     val formattedDate = remember(selectedDate) {
-        selectedDate.format(DATE_FORMATTER)
+        selectedDate.toKoreanFullDate()
     }
 
     val isFuture = remember(selectedDate) {