diff --git a/templates/size.h b/templates/size.h
new file mode 100644
index 00000000..8c859a85
--- /dev/null
+++ b/templates/size.h
@@ -0,0 +1,23 @@
+#include <cstddef>
+
+/**
+ * Get size of the given array.
+ *
+ * @param array An array
+ * @return Size of the array
+ */
+template <class T, std::size_t N>
+constexpr std::size_t size(const T (&array)[N]) noexcept {
+    return N;
+}
+
+/**
+ * Get size of the given container.
+ *
+ * @param c An container
+ * @return Size of the container
+ */
+template <class C>
+constexpr auto size(const C& c) -> decltype(c.size()) {
+    return c.size();
+}