diff --git a/README.md b/README.md
index 39e34d3..f714a9a 100644
--- a/README.md
+++ b/README.md
@@ -9,5 +9,12 @@ improvement over time, and thus over the programs I create. Some programs I
 have revisited for a more efficient implementation and gave them a small README
 detailing my algorithm.
 
+As a coding standard, I try to make code that can be run with:
+* Python 2.7
+* Python 3
+* Pypy
+
+Most of the code runs the fastest in Pypy, but there are exceptions.
+
 All this code is under MIT license. Use it for whatever you want, but please do
 credit me.