diff --git a/src/nostalgia/world/world.cpp b/src/nostalgia/world/world.cpp
index 31a2935b2..95baecdaa 100644
--- a/src/nostalgia/world/world.cpp
+++ b/src/nostalgia/world/world.cpp
@@ -36,7 +36,7 @@ void Zone::draw(Context *ctx) {
 	}
 }
 
-size_t Zone::size() {
+std::size_t Zone::size() {
 	return sizeof(Zone) + m_bounds.width * m_bounds.height * sizeof(Tile);
 }
 
diff --git a/src/nostalgia/world/world.hpp b/src/nostalgia/world/world.hpp
index 031e4c1f2..ff022adbc 100644
--- a/src/nostalgia/world/world.hpp
+++ b/src/nostalgia/world/world.hpp
@@ -51,7 +51,7 @@ struct Zone {
 
 		void draw(core::Context *ctx);
 
-		size_t size();
+		std::size_t size();
 
 		Tile *tile(int x, int y);