diff --git a/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddActivityViewModel.kt b/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddActivityViewModel.kt
index 29f1f48..4ce6d01 100644
--- a/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddActivityViewModel.kt
+++ b/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddActivityViewModel.kt
@@ -28,12 +28,14 @@ class CareerAddActivityViewModel : ViewModel() {
     val endDate: MutableLiveData<String> = MutableLiveData()
     val fileAddedEvent: MutableLiveData<Boolean> = MutableLiveData()
     val imageList: MutableList<MultipartBody.Part> = mutableListOf()
+    val totalFileSize = MutableLiveData<Long>(0)
 
     init {
         title.value = ""
         startDate.value = ""
         endDate.value = ""
         imageList.clear()
+        totalFileSize.value = 0
     }
 
     fun init() {
@@ -41,6 +43,7 @@ class CareerAddActivityViewModel : ViewModel() {
         startDate.value = ""
         endDate.value = ""
         imageList.clear()
+        totalFileSize.value = 0
     }
 
     /* 버튼 활성화 기능 */
@@ -48,22 +51,29 @@ class CareerAddActivityViewModel : ViewModel() {
         addSource(title) { value = areBothFieldsFilled() }
         addSource(startDate) { value = areBothFieldsFilled() }
         addSource(endDate) { value = areBothFieldsFilled() }
+        addSource(totalFileSize) { value = areBothFieldsFilled() }
     }
 
     private fun areBothFieldsFilled(): Boolean {
         return !(title.value.isNullOrEmpty() || title.value!!.contains(" ") || title.value!!.length > 20) && isDateValid(
             startDate.value
-        ) && isDateValid(endDate.value)
+        ) && isDateValid(endDate.value) && isFileSizeValid()
     }
 
     private fun isDateValid(date: String?): Boolean {
         return !date.isNullOrBlank() && date.length == 8
     }
 
+    //파일 사이즈가 30MB를 넘지 않는지 체크
+    private fun isFileSizeValid(): Boolean {
+        return totalFileSize.value ?: 0 <= 30 * 1024 * 1024
+    }
+
     fun addImageFile(file: File) {
         val requestFile = RequestBody.create("image/*".toMediaTypeOrNull(), file)
         val body = MultipartBody.Part.createFormData("image", file.name, requestFile)
         imageList.add(body)
+        calculateTotalFileSize() //파일 사이즈 계산
         fileAddedEvent.value = true
     }
 
@@ -93,9 +103,20 @@ class CareerAddActivityViewModel : ViewModel() {
         val filePart = MultipartBody.Part.createFormData("image", fileName, requestFile)
 
         imageList.add(filePart)
+        calculateTotalFileSize() //파일 사이즈 계산
         fileAddedEvent.value = true
     }
 
+    //파일 사이즈 측정
+    fun calculateTotalFileSize() {
+        var totalSize: Long = 0
+        for (filePart in imageList) {
+            val file = filePart.body
+            totalSize += file?.contentLength() ?: 0
+        }
+        totalFileSize.value = totalSize
+    }
+
     //API에 전송할 데이터를 포함하는 RequestDto 생성 함수
     fun createRequestDto(): ActivityDto? {
         val startDateString = startDate.value
@@ -135,18 +156,6 @@ class CareerAddActivityViewModel : ViewModel() {
         val requestDtoPart: RequestBody =
             requestDtoJson.toRequestBody("application/json".toMediaTypeOrNull())
 
-        //파일 사이즈 측정
-        fun calculateTotalFileSize(): Long {
-            var totalSize: Long = 0
-            for (filePart in imageList) {
-                val file = filePart.body
-                totalSize += file?.contentLength() ?: 0
-            }
-            return totalSize
-        }
-
-        val totalFileSize = calculateTotalFileSize()
-        Log.d("File Size", "Total File Size: $totalFileSize bytes")
         careerApiService.addCareer(imageList, requestDtoPart)
             .enqueue(object : Callback<AddCareerResponse> {
                 override fun onResponse(
@@ -158,7 +167,7 @@ class CareerAddActivityViewModel : ViewModel() {
                         if (addCareerResponse != null) {
                             _addedCareerInfo.postValue(addCareerResponse)
                             Log.d("addCareer:Extras 성공", "${response.body()}")
-                            Log.d("addSuccessFileName", imageList.toString())
+                            Log.d("totalFileSize", totalFileSize.value.toString())
                         } else {
                             _error.postValue("서버 응답이 올바르지 않습니다.")
                         }
diff --git a/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddVolunteerViewModel.kt b/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddVolunteerViewModel.kt
index eea2d43..24ec08d 100644
--- a/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddVolunteerViewModel.kt
+++ b/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerAddVolunteerViewModel.kt
@@ -43,9 +43,8 @@ class CareerAddVolunteerViewModel : ViewModel() {
     }
 
     private fun areBothFieldsFilled(): Boolean {
-        return !(title.value.isNullOrEmpty() || title.value!!.contains(" ") || title.value!!.length > 20) && isDateValid(
-            startDate.value
-        ) && isDateValid(endDate.value)
+        return !(title.value.isNullOrEmpty() || title.value!!.contains(" ") || title.value!!.length > 20) && !hour.value.isNullOrBlank()
+                && isDateValid(startDate.value) && isDateValid(endDate.value)
     }
 
     private fun isDateValid(date: String?): Boolean {
diff --git a/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerEditActivityViewModel.kt b/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerEditActivityViewModel.kt
index 3b577c6..016cf03 100644
--- a/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerEditActivityViewModel.kt
+++ b/app/src/main/java/umc/com/mobile/project/ui/career/viewmodel/CareerEditActivityViewModel.kt
@@ -36,6 +36,7 @@ class CareerEditActivityViewModel : ViewModel() {
     val addFilesLive: MutableLiveData<Boolean> = MutableLiveData<Boolean>().apply {
         value = addFiles.isNotEmpty()
     }
+    val totalFileSize = MutableLiveData<Long>(0)
 
     init {
         studentId.value = 0
@@ -44,6 +45,7 @@ class CareerEditActivityViewModel : ViewModel() {
         startDate.value = ""
         endDate.value = ""
         addFiles.clear()
+        totalFileSize.value = 0
     }
 
     fun init() {
@@ -53,6 +55,7 @@ class CareerEditActivityViewModel : ViewModel() {
         endDate.value = ""
         addFiles.clear()
         addFilesLive.value = addFiles.isNotEmpty()
+        totalFileSize.value = 0
     }
 
     val isFilledAnyOptions: LiveData<Boolean> = MediatorLiveData<Boolean>().apply {
@@ -61,21 +64,28 @@ class CareerEditActivityViewModel : ViewModel() {
         addSource(startDate) { value = isAnyFieldFilled() }
         addSource(endDate) { value = isAnyFieldFilled() }
         addSource(addFilesLive) { value = isAnyFieldFilled() }
+        addSource(totalFileSize) { value = isAnyFieldFilled() }
     }
 
     private fun isAnyFieldFilled(): Boolean {
-        return !title.value.isNullOrBlank() || !startDate.value.isNullOrBlank() || !endDate.value.isNullOrBlank() || (addFilesLive.value ?: false)
+        return (!title.value.isNullOrBlank() || !startDate.value.isNullOrBlank() || !endDate.value.isNullOrBlank() || addFilesLive.value ?: false) && isFileSizeValid()
     }
 
     private fun isDateValid(date: String?): Boolean {
         return date.isNullOrBlank() || date.length == 8
     }
 
+    //파일 사이즈가 30MB를 넘지 않는지 체크
+    private fun isFileSizeValid(): Boolean {
+        return totalFileSize.value ?: 0 <= 30 * 1024 * 1024
+    }
+
     fun addImageFile(file: File) {
         val requestFile = RequestBody.create("image/*".toMediaTypeOrNull(), file)
         val body = MultipartBody.Part.createFormData("addFiles", file.name, requestFile)
         addFiles.add(body)
         addFilesLive.value = addFiles.isNotEmpty()
+        calculateTotalFileSize() //파일 사이즈 계산
         fileAddedEvent.value = true
     }
 
@@ -105,9 +115,20 @@ class CareerEditActivityViewModel : ViewModel() {
         val filePart = MultipartBody.Part.createFormData("addFiles", fileName, requestFile)
         addFiles.add(filePart)
         addFilesLive.value = addFiles.isNotEmpty()
+        calculateTotalFileSize() //파일 사이즈 계산
         fileAddedEvent.value = true
     }
 
+    //파일 사이즈 측정
+    fun calculateTotalFileSize() {
+        var totalSize: Long = 0
+        for (filePart in addFiles) {
+            val file = filePart.body
+            totalSize += file?.contentLength() ?: 0
+        }
+        totalFileSize.value = totalSize
+    }
+
     private val careerApiService = ApiClient.createService<CareerApi>()
 
     private val _activityDetailInfo: MutableLiveData<CareerDetailResponse?> = MutableLiveData()