diff --git a/docat/docat/app.py b/docat/docat/app.py
index c6de7720..bc4a84b5 100644
--- a/docat/docat/app.py
+++ b/docat/docat/app.py
@@ -28,6 +28,7 @@
     UPLOAD_FOLDER,
     calculate_token,
     create_symlink,
+    directory_size,
     extract_archive,
     get_all_projects,
     get_project_details,
@@ -139,6 +140,10 @@ def upload_icon(
     with icon_path.open("wb") as buffer:
         shutil.copyfileobj(file.file, buffer)
 
+    # recalculate size cache
+    directory_size(project_base_path, recalculate=True)
+    directory_size(DOCAT_UPLOAD_FOLDER, recalculate=True)
+
     return ApiResponse(message="Icon successfully uploaded")
 
 
@@ -266,6 +271,10 @@ def upload(
     if not (base_path / "index.html").exists():
         return ApiResponse(message="Documentation uploaded successfully, but no index.html found at root of archive.")
 
+    # recalculate size cache
+    directory_size(project_base_path, recalculate=True)
+    directory_size(DOCAT_UPLOAD_FOLDER, recalculate=True)
+
     return ApiResponse(message="Documentation uploaded successfully")
 
 
@@ -372,6 +381,9 @@ def delete(
         response.status_code = status.HTTP_404_NOT_FOUND
         return ApiResponse(message=message)
 
+    # recalculate size cache
+    directory_size(DOCAT_UPLOAD_FOLDER, recalculate=True)
+
     return ApiResponse(message=f"Successfully deleted version '{version}'")
 
 
diff --git a/docat/docat/utils.py b/docat/docat/utils.py
index ac0f7199..6a4f45c1 100644
--- a/docat/docat/utils.py
+++ b/docat/docat/utils.py
@@ -93,6 +93,9 @@ def remove_docs(project: str, version: str, upload_folder_path: Path):
             if not link.resolve().exists():
                 link.unlink()
 
+        # remove size info
+        (upload_folder_path / project / ".size").unlink(missing_ok=True)
+
         # remove empty projects
         if not [d for d in docs.parent.iterdir() if d.is_dir()]:
             docs.parent.rmdir()
@@ -158,8 +161,19 @@ def readable_size(bytes: int) -> str:
     return str(amount) + size_suffix
 
 
-def directory_size(path: Path) -> int:
-    return sum(file.stat().st_size for file in path.rglob("*") if file.is_file())
+def directory_size(path: Path, recalculate: bool = False) -> int:
+    """
+    Returns the size of a directory and caches it's size unless
+    recalculate is set to true or the cache is missed
+    """
+    size_info = path / ".size"
+    if size_info.exists() and not recalculate:
+        return int(size_info.read_text())
+
+    dir_size = sum(file.stat().st_size for file in path.rglob("*") if file.is_file())
+    size_info.write_text(str(dir_size))  # cache directory size
+
+    return dir_size
 
 
 def get_system_stats(upload_folder_path: Path) -> Stats:
diff --git a/docat/tests/test_stats.py b/docat/tests/test_stats.py
index 166c4a9b..f1bfe7ba 100644
--- a/docat/tests/test_stats.py
+++ b/docat/tests/test_stats.py
@@ -9,10 +9,10 @@
 @pytest.mark.parametrize(
     ("project_config", "n_projects", "n_versions", "storage"),
     [
-        ([("some-project", ["1.0.0"])], 1, 1, "20 bytes"),
-        ([("some-project", ["1.0.0", "2.0.0"])], 1, 2, "40 bytes"),
-        ([("some-project", ["1.0.0", "2.0.0"])], 1, 2, "40 bytes"),
-        ([("some-project", ["1.0.0", "2.0.0"]), ("another-project", ["1"])], 2, 3, "60 bytes"),
+        ([("some-project", ["1.0.0"])], 1, 1, "22 bytes"),
+        ([("some-project", ["1.0.0", "2.0.0"])], 1, 2, "44 bytes"),
+        ([("some-project", ["1.0.0", "2.0.0"])], 1, 2, "44 bytes"),
+        ([("some-project", ["1.0.0", "2.0.0"]), ("another-project", ["1"])], 2, 3, "66 bytes"),
     ],
 )
 def test_get_stats(_, project_config, n_projects, n_versions, storage, client_with_claimed_project):
diff --git a/docat/tests/test_upload_icon.py b/docat/tests/test_upload_icon.py
index 1a22e447..03a04655 100644
--- a/docat/tests/test_upload_icon.py
+++ b/docat/tests/test_upload_icon.py
@@ -181,7 +181,7 @@ def test_get_project_recongizes_icon(_, client_with_claimed_project):
             {
                 "name": "some-project",
                 "logo": True,
-                "storage": "103 bytes",
+                "storage": "105 bytes",
                 "versions": [{"name": "1.0.0", "timestamp": "2000-01-01T01:01:00", "tags": [], "hidden": False}],
             }
         ]