diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1fee4b0..006250b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,13 +3,19 @@
 * Minor releases (X.1.X) are new features such as added functions or small changes that don't cause major compatibility issues.
 * Major releases (1.X.X) are major new features or changes that break backward compatibility in a big way.
 
-## [Latest](https://github.com/int-brain-lab/iblutil/commits/main) [1.9.0]
+## [Latest](https://github.com/int-brain-lab/iblutil/commits/main) [1.10.0]
+
+### Added
+
+- util.dir_size: method to determine size of directory in bytes
+
+## [1.9.0]
 
 ### Added
 
 - numerical.hash_uuids returns the hash of a collection of UUIDs
 
-## [Latest](https://github.com/int-brain-lab/iblutil/commits/main) [1.8.0]
+## [1.8.0]
 
 ### Modified
 
diff --git a/iblutil/__init__.py b/iblutil/__init__.py
index e5102d3..52af183 100644
--- a/iblutil/__init__.py
+++ b/iblutil/__init__.py
@@ -1 +1 @@
-__version__ = '1.9.0'
+__version__ = '1.10.0'
diff --git a/iblutil/util.py b/iblutil/util.py
index 470152d..e84c030 100644
--- a/iblutil/util.py
+++ b/iblutil/util.py
@@ -1,10 +1,12 @@
 from itertools import takewhile
+from os import scandir
 from pathlib import Path
 import collections
 import colorlog
 import copy
 import logging
 import sys
+from typing import Union
 
 import numpy as np
 
@@ -253,3 +255,31 @@ def rrmdir(folder: Path, levels: int = 0):
         to_remove = (folder, *[folder.parents[n] for n in range(levels)])
     # filter list to those that are empty; if statement always true as rmdir returns None
     return [f for f in takewhile(lambda f: not any(f.iterdir()), to_remove) if not f.rmdir()]
+
+
+def dir_size(directory: Union[str, Path], follow_symlinks: bool = False) -> int:
+    """
+    Calculate the total size of a directory including all its subdirectories and files.
+
+    Parameters
+    ----------
+    directory : str | Path
+        The path to the directory for which the size needs to be calculated.
+    follow_symlinks : bool, optional
+        Whether to follow symbolic links when calculating the size. Default is False.
+
+    Returns
+    -------
+    int
+        The total size of the directory in bytes.
+    """
+    total_bytes = 0
+    with scandir(directory) as it:
+        for entry in it:
+            if entry.is_symlink() and not follow_symlinks:
+                continue
+            elif entry.is_dir():
+                total_bytes += dir_size(entry.path, follow_symlinks)
+            elif entry.is_file():
+                total_bytes += entry.stat().st_size
+    return total_bytes
diff --git a/tests/test_util.py b/tests/test_util.py
index 5a49e4e..b58bda6 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -180,5 +180,27 @@ def test_rrmdir(self):
             self.assertTrue(file.exists())
 
 
+class TestDirSize(unittest.TestCase):
+
+    def test_dir_size(self):
+        with tempfile.TemporaryDirectory() as temp_dir:
+            dir1 = Path(temp_dir)
+            dir2 = Path(dir1).joinpath('sub_dir')
+            dir2.mkdir()
+            file1 = dir1.joinpath('file1')
+            file2 = dir2.joinpath('file2')
+            file3 = dir2.joinpath('file3')
+            with open(file1, 'w') as f1, open(file2, 'w') as f2, open(file3, 'w') as f3:
+                f1.write('Old pond')
+                f2.write('A frog jumps in')
+                f3.write('The sound of water')
+            symlink = dir2.joinpath('symlink_file')
+            symlink.symlink_to(file1)
+            expected = file1.stat().st_size + file2.stat().st_size + file3.stat().st_size
+            self.assertEqual(util.dir_size(str(dir1)), expected)
+            self.assertEqual(util.dir_size(dir1), expected)
+            self.assertEqual(util.dir_size(dir1, True), expected + file1.stat().st_size)
+
+
 if __name__ == '__main__':
     unittest.main(exit=False)