diff --git a/src/scope_equipment_activity/schema.py b/src/scope_equipment_activity/schema.py
index b0788bd..9da7f07 100644
--- a/src/scope_equipment_activity/schema.py
+++ b/src/scope_equipment_activity/schema.py
@@ -18,7 +18,7 @@ class ScopeEquipmentActivityCreate(ScopeEquipmentActivityBase):
 
 class ScopeEquipmentActivityUpdate(ScopeEquipmentActivityBase):
     name: Optional[str] = Field(None)
-    cost: Optional[str] = Field(0)
+    cost: Optional[float] = Field(0)
 
 
 class ScopeEquipmentActivityRead(ScopeEquipmentActivityBase):