diff --git a/src/mdevaluate/distribution.py b/src/mdevaluate/distribution.py
index f2d1982..d3c113e 100644
--- a/src/mdevaluate/distribution.py
+++ b/src/mdevaluate/distribution.py
@@ -2,6 +2,7 @@ import numpy as np
 from numpy.typing import ArrayLike
 from scipy import spatial
 from scipy.spatial import KDTree
+from scipy.sparse.csgraph import connected_components
 
 from .coordinates import rotate_axis, polar_coordinates, Coordinates, CoordinateFrame
 from .atoms import next_neighbors
@@ -432,3 +433,19 @@ def hbonds(
         )
     else:
         return pairs[is_bond]
+
+def calc_cluster_sizes(frame, r_max=0.35):
+    frame_PBC, indices_PBC = pbc_points(
+        frame, frame.box, thickness=r_max + 0.1, index=True
+    )
+    tree = KDTree(frame_PBC)
+    matrix = tree.sparse_distance_matrix(tree, r_max, output_type="ndarray")
+    new_matrix = np.zeros((len(frame), len(frame)))
+    for entry in matrix:
+        if entry[2] > 0:
+            new_matrix[indices_PBC[entry[0]], indices_PBC[entry[1]]] = 1
+    n_components, labels = connected_components(new_matrix, directed=False)
+    cluster_sizes = []
+    for i in range(0, np.max(labels) + 1):
+        cluster_sizes.append(np.sum(labels == i))
+    return np.array(cluster_sizes).flatten()
diff --git a/src/mdevaluate/utils.py b/src/mdevaluate/utils.py
index 42ad521..e2d3d29 100644
--- a/src/mdevaluate/utils.py
+++ b/src/mdevaluate/utils.py
@@ -498,5 +498,5 @@ def timing(function):
         time_needed = end_time - start_time
         print(f"Finished in {int(time_needed // 60)} min " f"{int(time_needed % 60)} s")
         return result
+    return wrap
 
-    return wrap
\ No newline at end of file