diff --git a/alib2std/src/extensions/range.hpp b/alib2std/src/extensions/range.hpp
index 0ab3881d55fb0d56615752b82bbf3563c05d365b..ec46fc3355c1d67f77e05452c8a44e8eb26bf6aa 100644
--- a/alib2std/src/extensions/range.hpp
+++ b/alib2std/src/extensions/range.hpp
@@ -59,7 +59,7 @@ public:
 		return m_begin == m_end;
 	}
 
-	constexpr difference_type size() const {
+	constexpr size_t size() const {
 		return std::distance ( m_begin, m_end );
 	}