diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
index 92b0305212..34e525eadd 100644
--- a/qapi/string-output-visitor.c
+++ b/qapi/string-output-visitor.c
@@ -52,7 +52,7 @@ static void print_type_number(Visitor *v, double *obj, const char *name,
                               Error **errp)
 {
     StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
-    string_output_set(sov, g_strdup_printf("%g", *obj));
+    string_output_set(sov, g_strdup_printf("%f", *obj));
 }
 
 char *string_output_get_string(StringOutputVisitor *sov)
diff --git a/tests/test-string-output-visitor.c b/tests/test-string-output-visitor.c
index 22909b84ef..608f14a5de 100644
--- a/tests/test-string-output-visitor.c
+++ b/tests/test-string-output-visitor.c
@@ -84,7 +84,7 @@ static void test_visitor_out_number(TestOutputVisitorData *data,
 
     str = string_output_get_string(data->sov);
     g_assert(str != NULL);
-    g_assert_cmpstr(str, ==, "3.14");
+    g_assert_cmpstr(str, ==, "3.140000");
     g_free(str);
 }