diff --git a/src/PackageModel/PackageDelegate.cpp b/src/PackageModel/PackageDelegate.cpp
--- a/src/PackageModel/PackageDelegate.cpp
+++ b/src/PackageModel/PackageDelegate.cpp
@@ -239,7 +239,7 @@
         }
         break;
     case 3:
-        text = index.data(PackageModel::InstalledSizeRole).toString();
+        text = index.data(PackageModel::InstalledSizeDisplayRole).toString();
         pen.setBrush(foregroundColor);
         break;
     case 4:
@@ -281,7 +281,7 @@
         size.setWidth(metric.width(index.data(PackageModel::ActionRole).toString()));
         break;
     case 3:
-        size.setWidth(metric.width(index.data(PackageModel::InstalledSizeRole).toString()));
+        size.setWidth(metric.width(index.data(PackageModel::InstalledSizeDisplayRole).toString()));
         break;
     case 4:
         size.setWidth(metric.width(index.data(PackageModel::InstalledVersionRole).toString()));
diff --git a/src/PackageModel/PackageModel.h b/src/PackageModel/PackageModel.h
--- a/src/PackageModel/PackageModel.h
+++ b/src/PackageModel/PackageModel.h
@@ -37,8 +37,9 @@
         StatusRole = Qt::UserRole + 4,
         SupportRole = Qt::UserRole + 5,
         InstalledSizeRole = Qt::UserRole + 6,
-        InstalledVersionRole = Qt::UserRole + 7,
-        AvailableVersionRole = Qt::UserRole + 8
+        InstalledSizeDisplayRole = Qt::UserRole + 7,
+        InstalledVersionRole = Qt::UserRole + 8,
+        AvailableVersionRole = Qt::UserRole + 9
     };
     explicit PackageModel(QObject *parent = 0);
 
diff --git a/src/PackageModel/PackageModel.cpp b/src/PackageModel/PackageModel.cpp
--- a/src/PackageModel/PackageModel.cpp
+++ b/src/PackageModel/PackageModel.cpp
@@ -64,6 +64,8 @@
     case SupportRole:
         return package->isSupported();
     case InstalledSizeRole:
+        return package->currentInstalledSize();
+    case InstalledSizeDisplayRole:
         if (package->isInstalled()) {
             return KFormat().formatByteSize(package->currentInstalledSize());
         }
diff --git a/src/PackageModel/PackageProxyModel.cpp b/src/PackageModel/PackageProxyModel.cpp
--- a/src/PackageModel/PackageProxyModel.cpp
+++ b/src/PackageModel/PackageProxyModel.cpp
@@ -207,6 +207,16 @@
           return packageStatusLessThan(leftPackage, rightPackage);
       case 2:
           return packageRequestedLessThan(leftPackage, rightPackage);
+      case 3: /* Installed size */
+          {
+              qlonglong leftSize = left.data(PackageModel::InstalledSizeRole).toLongLong();
+              qlonglong rightSize = right.data(PackageModel::InstalledSizeRole).toLongLong();
+              return leftSize < rightSize;
+          }
+      case 4: /* Installed version */
+          return QApt::Package::compareVersion(leftPackage->installedVersion(), rightPackage->installedVersion()) < 0;
+      case 5: /* Available version */
+          return QApt::Package::compareVersion(leftPackage->availableVersion(), rightPackage->availableVersion()) < 0;
     }
 
     return false;