diff --git a/src/conio/scale.c b/src/conio/scale.c
index a029b03929c24ab0ecbc59c5a2b64d25d8704710..6a9154c59437b977e9f0b691e73014d9372b09a8 100644
--- a/src/conio/scale.c
+++ b/src/conio/scale.c
@@ -1,6 +1,7 @@
 #include <math.h>
 #include <stdbool.h>
 #include <stdlib.h>
+#include <stdio.h>
 
 #include "ciolib.h"
 #include "scale.h"