diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 8f82f4f..3b5d331 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -4344,7 +4344,7 @@
 	}
 	if (prec < 0)
 		prec = 6;
-	if (type == 'f' && fabs(x)/1e25 >= 1e25)
+	if (type == 'f' && fabs(x) >= 1e50)
 		type = 'g';
 	/* Worst case length calc to ensure no buffer overrun: