diff --git a/core/include/kernel_defines.h b/core/include/kernel_defines.h
index 79c71973a5..48900d7011 100644
--- a/core/include/kernel_defines.h
+++ b/core/include/kernel_defines.h
@@ -108,6 +108,16 @@
 #define UNREACHABLE() do { /* nothing */ } while (1)
 #endif
 
+/**
+ * @def ARRAY_SIZE(a)
+ * @brief       Calculate the number of elements in a static array.
+ * @param[in]   a   Array to examine
+ * @returns     The number of elements in the array a.
+ */
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(a) (sizeof((a)) / sizeof((a)[0]))
+#endif
+
 /**
  * @def         ALIGN_OF(T)
  * @brief       Calculate the minimal alignment for type T.