diff --git a/arch/sandbox/Kconfig b/arch/sandbox/Kconfig
index 7b07bff..87418e3 100644
--- a/arch/sandbox/Kconfig
+++ b/arch/sandbox/Kconfig
@@ -35,4 +35,9 @@
 
 endchoice
 
+config SANDBOX_BITS_PER_LONG
+	int
+	default 32 if SANDBOX_32BIT
+	default 64 if SANDBOX_64BIT
+
 endmenu