diff --git a/emmet-core/emmet/core/vasp/task.py b/emmet-core/emmet/core/vasp/task.py
index 8db3d5a3a5..7301dd28fb 100644
--- a/emmet-core/emmet/core/vasp/task.py
+++ b/emmet-core/emmet/core/vasp/task.py
@@ -91,7 +91,10 @@ class RunStatistics(BaseModel):
     total_time: float = Field(
         None, description="The total CPU time for this calculation"
     )
-    cores: int = Field(None, description="The number of cores used by VASP")
+    cores: Union[int, str] = Field(
+        None,
+        description="The number of cores used by VASP (some clusters print `mpi-ranks` here)",
+    )
 
 
 class TaskDocument(StructureMetadata):