diff --git a/apps/openmw/mwbase/mechanicsmanager.hpp b/apps/openmw/mwbase/mechanicsmanager.hpp
index b8733259f..6cb7c6918 100644
--- a/apps/openmw/mwbase/mechanicsmanager.hpp
+++ b/apps/openmw/mwbase/mechanicsmanager.hpp
@@ -82,7 +82,10 @@ namespace MWBase
 
             virtual int getDerivedDisposition(const MWWorld::Ptr& ptr) = 0;
             ///< Calculate the diposition of an NPC toward the player.
-            
+
+            virtual float getArmorRating (const MWWorld::Ptr& ptr) = 0;
+            ///< Calculate the combined armor rating of an NPC.
+
             virtual int countDeaths (const std::string& id) const = 0;
             ///< Return the number of deaths for actors with the given ID.
 
diff --git a/apps/openmw/mwgui/inventorywindow.cpp b/apps/openmw/mwgui/inventorywindow.cpp
index ab7615c0e..2caed7972 100644
--- a/apps/openmw/mwgui/inventorywindow.cpp
+++ b/apps/openmw/mwgui/inventorywindow.cpp
@@ -13,6 +13,7 @@
 #include "../mwbase/environment.hpp"
 #include "../mwbase/soundmanager.hpp"
 #include "../mwbase/windowmanager.hpp"
+#include "../mwbase/mechanicsmanager.hpp"
 
 #include "../mwworld/containerstore.hpp"
 #include "../mwworld/class.hpp"
@@ -50,6 +51,7 @@ namespace MWGui
         getWidget(mFilterMisc, "MiscButton");
         getWidget(mLeftPane, "LeftPane");
         getWidget(mRightPane, "RightPane");
+        getWidget(mArmorRating, "ArmorRating");
 
         mAvatar->eventMouseButtonClick += MyGUI::newDelegate(this, &InventoryWindow::onAvatarClicked);
 
@@ -288,6 +290,9 @@ namespace MWGui
         mPreview.update (size.width, size.height);
         mAvatarImage->setSize(MyGUI::IntSize(std::max(mAvatar->getSize().width, 512), std::max(mAvatar->getSize().height, 1024)));
         mAvatarImage->setImageTexture("CharacterPreview");
+
+        mArmorRating->setCaptionWithReplacing ("#{sArmor}: "
+            + boost::lexical_cast<std::string>(static_cast<int>(MWBase::Environment::get().getMechanicsManager()->getArmorRating(mPtr))));
     }
 
     void InventoryWindow::pickUpObject (MWWorld::Ptr object)
diff --git a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
index c9e4c77ea..c19b84cd8 100644
--- a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
+++ b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
@@ -2,6 +2,7 @@
 #include "mechanicsmanagerimp.hpp"
 
 #include "../mwworld/esmstore.hpp"
+#include "../mwworld/inventorystore.hpp"
 
 #include "../mwbase/environment.hpp"
 #include "../mwbase/world.hpp"
@@ -668,4 +669,52 @@ namespace MWMechanics
             mActors.skipAnimation(ptr);
     }
 
+    float MechanicsManager::getArmorRating(const MWWorld::Ptr &ptr)
+    {
+        MWWorld::InventoryStore& invStore = MWWorld::Class::get(ptr).getInventoryStore(ptr);
+        const MWWorld::Store<ESM::GameSetting> &gmst =
+            MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>();
+
+        int ratings[MWWorld::InventoryStore::Slots];
+
+        int iBaseArmorSkill = gmst.find("iBaseArmorSkill")->getInt();
+        float fUnarmoredBase1 = gmst.find("fUnarmoredBase1")->getFloat();
+        float fUnarmoredBase2 = gmst.find("fUnarmoredBase2")->getFloat();
+        int unarmoredSkill = MWWorld::Class::get(ptr).getNpcStats(ptr).getSkill(ESM::Skill::Unarmored).getModified();
+
+        for (int i = 0; i < MWWorld::InventoryStore::Slots; ++i)
+        {
+            MWWorld::ContainerStoreIterator it = invStore.getSlot(i);
+            if (it == invStore.end() || it->getTypeName() != typeid(ESM::Armor).name())
+            {
+                // unarmored
+                ratings[i] = (fUnarmoredBase1 * unarmoredSkill) * (fUnarmoredBase2 * unarmoredSkill);
+            }
+            else
+            {
+                MWWorld::LiveCellRef<ESM::Armor> *ref =
+                    it->get<ESM::Armor>();
+
+                int armorSkillType = MWWorld::Class::get(*it).getEquipmentSkill(*it);
+                int armorSkill = MWWorld::Class::get(ptr).getNpcStats(ptr).getSkill(armorSkillType).getModified();
+
+                if (ref->mBase->mData.mWeight == 0)
+                    ratings[i] = ref->mBase->mData.mArmor;
+                else
+                    ratings[i] = ref->mBase->mData.mArmor * armorSkill / iBaseArmorSkill;
+            }
+        }
+
+        float shield = MWWorld::Class::get(ptr).getCreatureStats(ptr).getMagicEffects().get(3).mMagnitude;
+
+        return ratings[MWWorld::InventoryStore::Slot_Cuirass] * 0.3
+                + (ratings[MWWorld::InventoryStore::Slot_CarriedLeft] + ratings[MWWorld::InventoryStore::Slot_Helmet]
+                    + ratings[MWWorld::InventoryStore::Slot_Greaves] + ratings[MWWorld::InventoryStore::Slot_Boots]
+                    + ratings[MWWorld::InventoryStore::Slot_LeftPauldron] + ratings[MWWorld::InventoryStore::Slot_RightPauldron]
+                    ) * 0.1
+                + (ratings[MWWorld::InventoryStore::Slot_LeftGauntlet] + MWWorld::InventoryStore::Slot_RightGauntlet)
+                    * 0.05
+                + shield;
+    }
+
 }
diff --git a/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp b/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp
index 5ad870571..2e09c5f8e 100644
--- a/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp
+++ b/apps/openmw/mwmechanics/mechanicsmanagerimp.hpp
@@ -88,6 +88,9 @@ namespace MWMechanics
             virtual int getDerivedDisposition(const MWWorld::Ptr& ptr);
             ///< Calculate the diposition of an NPC toward the player.
 
+            virtual float getArmorRating (const MWWorld::Ptr& ptr);
+            ///< Calculate the combined armor rating of an NPC.
+
             virtual int countDeaths (const std::string& id) const;
             ///< Return the number of deaths for actors with the given ID.
             
diff --git a/files/mygui/openmw_inventory_window.layout b/files/mygui/openmw_inventory_window.layout
index 88cc5638d..41bd40f92 100644
--- a/files/mygui/openmw_inventory_window.layout
+++ b/files/mygui/openmw_inventory_window.layout
@@ -17,7 +17,6 @@
                     <Property key="NeedMouse" value="false"/>
                 </Widget>
                 <Widget type="TextBox" skin="ProgressText" position="0 150 212 24" align="HCenter Bottom" name="ArmorRating">
-                    <Property key="Caption" value="Armor Rating"/>
                     <Property key="NeedMouse" value="false"/>
                 </Widget>
             </Widget>