diff --git a/invenio_communities/errors.py b/invenio_communities/errors.py
index 3c8d985af..7f5a4f49c 100644
--- a/invenio_communities/errors.py
+++ b/invenio_communities/errors.py
@@ -12,6 +12,8 @@
 from flask_babel import ngettext
 from invenio_i18n import gettext as _
 
+from .utils import humanize_byte_size
+
 
 class CommunityError(Exception):
     """Base exception for community errors."""
@@ -44,10 +46,15 @@ class LogoSizeLimitError(CommunityError):
 
     def __init__(self, limit, file_size):
         """Initialise error."""
+        limit_value, limit_unit = humanize_byte_size(limit)
+        file_size_value, file_size_unit = humanize_byte_size(file_size)
         super().__init__(
             _(
-                "Logo size limit exceeded. Limit: {limit} bytes Given: {file_size} bytes".format(
-                    limit=ceil(limit), file_size=ceil(file_size)
+                "Logo size limit exceeded. Limit: {limit_value} {limit_unit} Given: {file_size_value} {file_size_unit}".format(
+                    limit_value=limit_value,
+                    limit_unit=limit_unit,
+                    file_size_value=file_size_value,
+                    file_size_unit=file_size_unit,
                 )
             )
         )
diff --git a/invenio_communities/utils.py b/invenio_communities/utils.py
index 0d4a7dddd..0258d4c80 100644
--- a/invenio_communities/utils.py
+++ b/invenio_communities/utils.py
@@ -8,6 +8,8 @@
 
 """Utilities."""
 
+from decimal import ROUND_HALF_UP, Decimal
+
 from flask import session
 from flask_principal import Identity
 from invenio_accounts.models import Role
@@ -109,3 +111,14 @@ def on_datastore_post_commit(sender, session):
             users = role.users.all()
             for user in users:
                 on_user_membership_change(Identity(user.id))
+
+
+def humanize_byte_size(size):
+    """Converts bytes to largest unit (e.g., KB, MB, GB)."""
+    BYTES_PER_UNIT = 1000
+    s = Decimal(size)
+    q = Decimal("0.00")
+    for unit in ["B", "KB", "MB", "GB", "TB", "PB"]:
+        if s < BYTES_PER_UNIT:
+            return s.quantize(q, rounding=ROUND_HALF_UP), unit
+        s /= BYTES_PER_UNIT
diff --git a/tests/communities/test_resources.py b/tests/communities/test_resources.py
index 07059cf61..df32263d9 100644
--- a/tests/communities/test_resources.py
+++ b/tests/communities/test_resources.py
@@ -689,6 +689,9 @@ def test_logo_max_content_length(
         data=BytesIO(logo_data),
     )
     assert res.status_code == 400
+    assert (
+        res.json["message"] == "Logo size limit exceeded. Limit: 1.00 MB Given: 4.00 MB"
+    )
 
     # Update logo with small content
     logo_data = b"logo"