diff --git a/spoolman/api/v1/field.py b/spoolman/api/v1/field.py
index 0f1504c..9efcba7 100644
--- a/spoolman/api/v1/field.py
+++ b/spoolman/api/v1/field.py
@@ -59,7 +59,7 @@ async def update(
     key: Annotated[str, Path(min_length=1, max_length=64, regex="^[a-z0-9_]+$")],
     body: ExtraFieldParameters,
 ) -> Union[list[ExtraField], JSONResponse]:
-    body_with_key = ExtraField.parse_obj(body.copy(update={"key": key}))
+    body_with_key = ExtraField.parse_obj(body.copy(update={"key": key, "entity_type": entity_type}))
 
     try:
         await add_or_update_extra_field(db, entity_type, body_with_key)
diff --git a/spoolman/extra_fields.py b/spoolman/extra_fields.py
index ca003a2..83e5c18 100644
--- a/spoolman/extra_fields.py
+++ b/spoolman/extra_fields.py
@@ -36,7 +36,6 @@ class ExtraFieldType(Enum):
 class ExtraFieldParameters(BaseModel):
     name: str = Field(description="Nice name", min_length=1, max_length=128)
     unit: Optional[str] = Field(None, description="Unit of the value", min_length=1, max_length=16)
-    entity_type: EntityType = Field(description="Entity type this field is for")
     field_type: ExtraFieldType = Field(description="Type of the field")
     default_value: Optional[str] = Field(None, description="Default value of the field")
     choices: Optional[list[str]] = Field(None, description="Choices for the field, only for field type choice")
@@ -45,6 +44,7 @@ class ExtraFieldParameters(BaseModel):
 
 class ExtraField(ExtraFieldParameters):
     key: str = Field(description="Unique key", regex="^[a-z0-9_]+$", min_length=1, max_length=64)
+    entity_type: EntityType = Field(description="Entity type this field is for")
 
 
 def validate_extra_field_value(field: ExtraFieldParameters, value: str) -> None:  # noqa: C901, PLR0912