diff --git a/classquiz/routers/storage.py b/classquiz/routers/storage.py
index 7c64025..e20bd02 100644
--- a/classquiz/routers/storage.py
+++ b/classquiz/routers/storage.py
@@ -118,7 +118,9 @@ async def download_file_head(file_name: str) -> Response:
 
 
 @router.post("/")
-async def upload_file(file: UploadFile = File(), user: User = Depends(get_current_user)) -> PublicStorageItem:
+async def upload_file(
+    request: Request, file: UploadFile = File(), user: User = Depends(get_current_user)
+) -> PublicStorageItem:
     if file.content_type not in ALLOWED_MIME_TYPES:
         raise HTTPException(status_code=422, detail="Unsupported")
     if user.storage_used > settings.free_storage_limit:
@@ -135,7 +137,12 @@ async def upload_file(file: UploadFile = File(), user: User = Depends(get_curren
         deleted_at=None,
         alt_text=None,
     )
-    await storage.upload(file_name=file_id.hex, file_data=file.file, mime_type=file.content_type)
+    await storage.upload(
+        file_name=file_id.hex,
+        file_data=file.file,
+        mime_type=file.content_type,
+        size=request.headers.get("Content-Length"),
+    )
     await file_obj.save()
     await arq.enqueue_job("calculate_hash", file_id.hex)
     return PublicStorageItem.from_db_model(file_obj)
diff --git a/classquiz/storage/__init__.py b/classquiz/storage/__init__.py
index e90e9c7..90b277c 100644
--- a/classquiz/storage/__init__.py
+++ b/classquiz/storage/__init__.py
@@ -46,8 +46,10 @@ class Storage:
     def download(self, file_name: str) -> Generator | None:
         return self.instance.download(file_name)
 
-    async def upload(self, file_name: str, file_data: BinaryIO, mime_type: str | None = None) -> None:
-        return await self.instance.upload(file=file_data, file_name=file_name, mime_type=mime_type)
+    async def upload(
+        self, file_name: str, file_data: BinaryIO, mime_type: str | None = None, size: int | None = None
+    ) -> None:
+        return await self.instance.upload(file=file_data, file_name=file_name, mime_type=mime_type, size=size)
 
     async def delete(self, file_names: [str]) -> None:
         return await self.instance.delete(file_names=file_names)
diff --git a/classquiz/storage/local_storage.py b/classquiz/storage/local_storage.py
index 3a6f1d4..1404e11 100644
--- a/classquiz/storage/local_storage.py
+++ b/classquiz/storage/local_storage.py
@@ -29,7 +29,13 @@ class LocalStorage:
             yield None
 
     # skipcq: PYL-W0613
-    async def upload(self, file_name: str, file: BinaryIO, mime_type: str | None = None) -> None:
+    async def upload(
+        self,
+        file_name: str,
+        file: BinaryIO,
+        size: int | None,
+        mime_type: str | None = None,
+    ) -> None:
         with open(file=os.path.join(self.base_path, file_name), mode="wb") as f:
             copyfileobj(file, f)
 
diff --git a/classquiz/storage/s3_storage.py b/classquiz/storage/s3_storage.py
index 913d80e..af2832b 100644
--- a/classquiz/storage/s3_storage.py
+++ b/classquiz/storage/s3_storage.py
@@ -5,7 +5,6 @@
 
 import hashlib
 import hmac
-import sys
 from datetime import datetime, timedelta
 from typing import Tuple, BinaryIO, Generator
 
@@ -109,9 +108,9 @@ class S3Storage:
         return headers, request_url
 
     # skipcq: PYL-W0613
-    async def upload(self, file: BinaryIO, file_name: str, mime_type: str | None = "application/octet-stream") -> None:
+    async def upload(self, file: BinaryIO, file_name: str, size: int | None, mime_type: str | None = None) -> None:
         headers, url = self._generate_aws_signature_v4(method="PUT", path=f"/{file_name}")
-        headers["Content-Length"] = sys.getsizeof(file)
+        headers["Content-Length"] = size
         async with ClientSession() as session, session.put(url, headers=headers, data=file) as resp:
             if resp.status == 200:
                 return None