diff --git a/bdk/utils/types.h b/bdk/utils/types.h
index 2059bab..8418da0 100644
--- a/bdk/utils/types.h
+++ b/bdk/utils/types.h
@@ -23,7 +23,7 @@
 #define NULL ((void *)0)
 
 #define ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
-#define ALIGN_DOWN(x, a) (((x) - ((a) - 1)) & ~((a) - 1))
+#define ALIGN_DOWN(x, a) ((x) & ~((a) - 1))
 #define BIT(n) (1U << (n))
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 #define MIN(a, b) ((a) < (b) ? (a) : (b))