diff --git a/openpype/modules/kitsu/utils/update_op_with_zou.py b/openpype/modules/kitsu/utils/update_op_with_zou.py
index 15e6dd70d9..93d0d5e3fb 100644
--- a/openpype/modules/kitsu/utils/update_op_with_zou.py
+++ b/openpype/modules/kitsu/utils/update_op_with_zou.py
@@ -111,18 +111,18 @@ def update_op_assets(
         except (TypeError, ValueError):
             frame_in = 1001
         item_data["frameStart"] = frame_in
-        # Frames duration, fallback on 0
+        # Frames duration, fallback on 1
         try:
             # NOTE nb_frames is stored directly in item
             # because of zou's legacy design
-            frames_duration = int(item.get("nb_frames", 0))
+            frames_duration = int(item.get("nb_frames", 1))
         except (TypeError, ValueError):
             frames_duration = None
         # Frame out, fallback on frame_in + duration or project's value or 1001
         frame_out = item_data.pop("frame_out", None)
         if not frame_out:
             if frames_duration:
-                frame_out = frame_in + frames_duration
+                frame_out = frame_in + frames_duration - 1
             else:
                 frame_out = project_doc["data"].get("frameEnd", 1001)
         item_data["frameEnd"] = frame_out
diff --git a/openpype/modules/kitsu/utils/update_zou_with_op.py b/openpype/modules/kitsu/utils/update_zou_with_op.py
index b13c2dd4c6..b1a9b8b82c 100644
--- a/openpype/modules/kitsu/utils/update_zou_with_op.py
+++ b/openpype/modules/kitsu/utils/update_zou_with_op.py
@@ -174,7 +174,8 @@ def sync_zou_from_op_project(
                 doc["name"],
                 frame_in=doc["data"]["frameStart"],
                 frame_out=doc["data"]["frameEnd"],
-                nb_frames=doc["data"]["frameEnd"] - doc["data"]["frameStart"],
+                nb_frames=(
+                    doc["data"]["frameEnd"] - doc["data"]["frameStart"] + 1),
             )
 
         elif match.group(2):  # Sequence
@@ -229,7 +230,7 @@ def sync_zou_from_op_project(
                             "frame_in": frame_in,
                             "frame_out": frame_out,
                         },
-                        "nb_frames": frame_out - frame_in,
+                        "nb_frames": frame_out - frame_in + 1,
                     }
                 )
             entity = gazu.raw.update("entities", zou_id, entity_data)