diff --git a/quarters/readme.md b/quarters/readme.md
index 77c214f..298f9e5 100644
--- a/quarters/readme.md
+++ b/quarters/readme.md
@@ -1,6 +1,6 @@
 More info here:
 
-http://www.40percent.club/2018/03/happy_pi_day.html
+http://www.40percent.club/2018/03/happy-pi-day.html
 
 [How to order PCBs from gerber files](http://www.40percent.club/2017/03/ordering-pcb.html)