diff --git a/python/port/mpconfigport.h b/python/port/mpconfigport.h
index 53c3bb90a..5fb249736 100644
--- a/python/port/mpconfigport.h
+++ b/python/port/mpconfigport.h
@@ -105,6 +105,9 @@
 // Whether to include: randrange, randint, choice, random, uniform
 #define MICROPY_PY_URANDOM_EXTRA_FUNCS (1)
 
+// Whether to support rounding of integers (incl bignum); eg round(123,-1)=120
+#define MICROPY_PY_BUILTINS_ROUND_INT (1)
+
 // Function to seed URANDOM with on init
 #define MICROPY_PY_URANDOM_SEED_INIT_FUNC micropython_port_random()