diff --git a/Makefile b/Makefile
index 1eee738..cbdc831 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,3 @@
 ph7: ph7.c
-    gcc -o ph7 ph7.c examples/ph7_intro.c -W -Wall -Ofast
+    gcc -o ph7 ph7.c examples/ph7_intro.c -W -Wall -OFast