diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -125,9 +125,9 @@ static bool EngineNumberSorter(const GUI
  */
 static bool EngineIntroDateSorter(const GUIEngineListItem &a, const GUIEngineListItem &b)
 {
-	const int va = Engine::Get(a.engine_id)->intro_date;
-	const int vb = Engine::Get(b.engine_id)->intro_date;
-	const int r = va - vb;
+	const auto va = Engine::Get(a.engine_id)->intro_date;
+	const auto vb = Engine::Get(b.engine_id)->intro_date;
+	const auto r = va - vb;
 
 	/* Use EngineID to sort instead since we want consistent sorting */
 	if (r == 0) return EngineNumberSorter(a, b);
diff --git a/src/network/network_gui.cpp b/src/network/network_gui.cpp
--- a/src/network/network_gui.cpp
+++ b/src/network/network_gui.cpp
@@ -324,14 +324,14 @@ protected:
 	/** Sort servers by current date */
 	static bool NGameDateSorter(NetworkGameList * const &a, NetworkGameList * const &b)
 	{
-		int r = a->info.game_date - b->info.game_date;
+		auto r = a->info.game_date - b->info.game_date;
 		return (r != 0) ? r < 0 : NGameClientSorter(a, b);
 	}
 
 	/** Sort servers by the number of days the game is running */
 	static bool NGameYearsSorter(NetworkGameList * const &a, NetworkGameList * const &b)
 	{
-		int r = a->info.game_date - a->info.start_date - b->info.game_date + b->info.start_date;
+		auto r = a->info.game_date - a->info.start_date - b->info.game_date + b->info.start_date;
 		return (r != 0) ? r < 0: NGameDateSorter(a, b);
 	}
 
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -1360,7 +1360,7 @@ static bool VehicleNameSorter(const Vehi
 /** Sort vehicles by their age */
 static bool VehicleAgeSorter(const Vehicle * const &a, const Vehicle * const &b)
 {
-	int r = a->age - b->age;
+	auto r = a->age - b->age;
 	return (r != 0) ? r < 0 : VehicleNumberSorter(a, b);
 }