diff --git a/src/blenderbim/blenderbim/bim/data/pset/EPset_Productivity.ifc b/src/blenderbim/blenderbim/bim/data/pset/EPset_Productivity.ifc
new file mode 100644
index 0000000000..283946eb80
--- /dev/null
+++ b/src/blenderbim/blenderbim/bim/data/pset/EPset_Productivity.ifc
@@ -0,0 +1,13 @@
+ISO-10303-21;
+HEADER;
+FILE_DESCRIPTION((),'2;1');
+FILE_NAME('EPset_Productivity.ifc','2020-01-01T00:00:00',(),(),'EPset_Productivity','EPset_Productivity',$);
+FILE_SCHEMA(('IFC4'));
+ENDSEC;
+DATA;
+#1=IFCPROPERTYSETTEMPLATE('24XxTA2ED4o83uiZBG59D_',$,'EPset_Productivity','',.PSET_TYPEDRIVENOVERRIDE.,'IfcConstructionEquipmentResource,IfcLaborResource',(#2,#3,#4));
+#2=IFCSIMPLEPROPERTYTEMPLATE('3mL27FQ4X4MQn5fiGqIt8x',$,'BaseQuantityConsumed','',.P_SINGLEVALUE.,'IfcDuration',$,$,$,$,$,.READWRITE.);
+#3=IFCSIMPLEPROPERTYTEMPLATE('1DdJt5_Ar2mR4UDpO$98Ws',$,'BaseQuantityProducedName','',.P_SINGLEVALUE.,'IfcLabel',$,$,$,$,$,.READWRITE.);
+#4=IFCSIMPLEPROPERTYTEMPLATE('2OZPZ$Onb2gOvW20q7gacH',$,'BaseQuantityProducedValue','',.P_SINGLEVALUE.,'IfcReal',$,$,$,$,$,.READWRITE.);
+ENDSEC;
+END-ISO-10303-21;
diff --git a/src/blenderbim/blenderbim/bim/module/resource/__init__.py b/src/blenderbim/blenderbim/bim/module/resource/__init__.py
index 8794902494..cb2f056939 100644
--- a/src/blenderbim/blenderbim/bim/module/resource/__init__.py
+++ b/src/blenderbim/blenderbim/bim/module/resource/__init__.py
@@ -36,6 +36,7 @@ classes = (
     operator.EnableEditingResourceTime,
     operator.EditResourceTime,
     operator.DisableEditingResourceTime,
+    operator.CalculateResourceWork,
     prop.Resource,
     prop.BIMResourceProperties,
     prop.BIMResourceTreeProperties,
diff --git a/src/blenderbim/blenderbim/bim/module/resource/operator.py b/src/blenderbim/blenderbim/bim/module/resource/operator.py
index 34b70a80f4..34dbdd12be 100644
--- a/src/blenderbim/blenderbim/bim/module/resource/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/resource/operator.py
@@ -371,3 +371,17 @@ class EditResourceTime(bpy.types.Operator):
                 return True
             attributes[prop.name] = helper.parse_duration(prop.string_value)
             return True
+
+
+class CalculateResourceWork(bpy.types.Operator):
+    bl_idname = "bim.calculate_resource_work"
+    bl_label = "Calculate Resource Work"
+    bl_options = {"REGISTER", "UNDO"}
+    resource: bpy.props.IntProperty()
+
+    def execute(self, context):
+        self.file = IfcStore.get_file()
+        ifcopenshell.api.run("resource.calculate_resource_work", self.file, resource=self.file.by_id(self.resource))
+        Data.load(self.file)
+        bpy.ops.bim.load_resources()
+        return {"FINISHED"}
diff --git a/src/blenderbim/blenderbim/bim/module/resource/ui.py b/src/blenderbim/blenderbim/bim/module/resource/ui.py
index 8c63c25cab..ec10d592df 100644
--- a/src/blenderbim/blenderbim/bim/module/resource/ui.py
+++ b/src/blenderbim/blenderbim/bim/module/resource/ui.py
@@ -75,13 +75,21 @@ class BIM_PT_resources(Panel):
             and Data.resources[self.tprops.resources[self.props.active_resource_index].ifc_definition_id]["type"]
             != "IfcSubContractResource"
         ):
+            ifc_definition_id = self.tprops.resources[self.props.active_resource_index].ifc_definition_id
+
             row = self.layout.row(align=True)
             for ifc_class, icon in icon_map.items():
                 label = ifc_class.replace("Ifc", "").replace("Construction", "").replace("Resource", "")
                 op = row.operator("bim.add_resource", text=label, icon=icon)
-                op.resource = self.tprops.resources[self.props.active_resource_index].ifc_definition_id
+                op.resource = ifc_definition_id
                 op.ifc_class = ifc_class
 
+            row = self.layout.row(align=True)
+            row.alignment = "RIGHT"
+
+            op = row.operator("bim.calculate_resource_work", text="", icon="TEMP")
+            op.resource = ifc_definition_id
+
         self.layout.template_list(
             "BIM_UL_resources",
             "",
diff --git a/src/blenderbim/blenderbim/bim/module/sequence/__init__.py b/src/blenderbim/blenderbim/bim/module/sequence/__init__.py
index 1997e93671..2522c36759 100644
--- a/src/blenderbim/blenderbim/bim/module/sequence/__init__.py
+++ b/src/blenderbim/blenderbim/bim/module/sequence/__init__.py
@@ -98,7 +98,7 @@ classes = (
     operator.LoadTaskInputs,
     operator.LoadTaskResources,
     operator.LoadTaskOutputs,
-    operator.DeriveTaskDuration,
+    operator.CalculateTaskDuration,
     prop.WorkPlan,
     prop.BIMWorkPlanProperties,
     prop.Task,
diff --git a/src/blenderbim/blenderbim/bim/module/sequence/operator.py b/src/blenderbim/blenderbim/bim/module/sequence/operator.py
index 00c0e8bfd3..b908d80bab 100644
--- a/src/blenderbim/blenderbim/bim/module/sequence/operator.py
+++ b/src/blenderbim/blenderbim/bim/module/sequence/operator.py
@@ -797,6 +797,7 @@ class AssignProduct(bpy.types.Operator):
                 related_object=self.file.by_id(self.task),
             )
         Data.load(self.file)
+        bpy.ops.bim.load_task_outputs()
         return {"FINISHED"}
 
 
@@ -825,6 +826,7 @@ class UnassignProduct(bpy.types.Operator):
                 related_object=self.file.by_id(self.task),
             )
         Data.load(self.file)
+        bpy.ops.bim.load_task_outputs()
         return {"FINISHED"}
 
 
@@ -2106,9 +2108,9 @@ class LoadTaskOutputs(bpy.types.Operator):
         return {"FINISHED"}
 
 
-class DeriveTaskDuration(bpy.types.Operator):
-    bl_idname = "bim.derive_task_duration"
-    bl_label = "Derive Task Duration"
+class CalculateTaskDuration(bpy.types.Operator):
+    bl_idname = "bim.calculate_task_duration"
+    bl_label = "Calculate Task Duration"
     bl_options = {"REGISTER", "UNDO"}
     task: bpy.props.IntProperty()
 
diff --git a/src/blenderbim/blenderbim/bim/module/sequence/ui.py b/src/blenderbim/blenderbim/bim/module/sequence/ui.py
index 42dea09f5e..37c4bd138e 100644
--- a/src/blenderbim/blenderbim/bim/module/sequence/ui.py
+++ b/src/blenderbim/blenderbim/bim/module/sequence/ui.py
@@ -371,7 +371,7 @@ class BIM_PT_task_icom(Panel):
         row2 = col.row(align=True)
         row2.label(text="Resources")
 
-        op = row2.operator("bim.derive_task_duration", text="", icon="TIME")
+        op = row2.operator("bim.calculate_task_duration", text="", icon="TEMP")
         op.task = task.ifc_definition_id
 
         total_resources = len(context.scene.BIMResourceTreeProperties.resources)
diff --git a/src/ifcopenshell-python/ifcopenshell/api/resource/calculate_resource_work.py b/src/ifcopenshell-python/ifcopenshell/api/resource/calculate_resource_work.py
new file mode 100644
index 0000000000..aa68a8fe54
--- /dev/null
+++ b/src/ifcopenshell-python/ifcopenshell/api/resource/calculate_resource_work.py
@@ -0,0 +1,56 @@
+import math
+import ifcopenshell.api
+import ifcopenshell.util.date
+import ifcopenshell.util.element
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"resource": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        self.productivity = ifcopenshell.util.element.get_psets(self.settings["resource"]).get(
+            "EPset_Productivity", None
+        )
+        if not self.productivity:
+            return
+        unit_consumed = self.get_unit_consumed()
+        self.unit_produced_name = self.productivity.get("BaseQuantityProducedName", None)
+        unit_produced = self.productivity.get("BaseQuantityProducedValue", None)
+        total_produced = self.get_total_produced()
+        if not unit_consumed or not unit_produced or not total_produced:
+            return
+        seconds_worked = total_produced / unit_produced * unit_consumed
+        self.set_schedule_work(seconds_worked)
+
+    def get_unit_consumed(self):
+        duration = self.productivity.get("BaseQuantityConsumed", None)
+        if not duration:
+            return
+        return ifcopenshell.util.date.ifc2datetime(duration).seconds
+
+    def get_total_produced(self):
+        total = 0
+        for rel in self.settings["resource"].HasAssignments or []:
+            if not rel.is_a("IfcRelAssignsToProcess"):
+                continue
+            for rel2 in rel.RelatingProcess.HasAssignments or []:
+                if not rel2.is_a("IfcRelAssignsToProduct"):
+                    continue
+                psets = ifcopenshell.util.element.get_psets(rel2.RelatingProduct)
+                for pset in psets.values():
+                    for name, value in pset.items():
+                        if name == self.unit_produced_name:
+                            try:
+                                total += float(value)
+                            except:
+                                pass
+        return total
+
+    def set_schedule_work(self, seconds):
+        if not self.settings["resource"].Usage:
+            ifcopenshell.api.run("resource.add_resource_time", self.file, resource=self.settings["resource"])
+        self.settings["resource"].Usage.ScheduleWork = f"PT{seconds / 60 / 60}H"