diff --git a/src/main/java/me/hatter/math/util/MathUtil.java b/src/main/java/me/hatter/math/util/MathUtil.java
index 5b87d06..2e7cb41 100644
--- a/src/main/java/me/hatter/math/util/MathUtil.java
+++ b/src/main/java/me/hatter/math/util/MathUtil.java
@@ -13,6 +13,11 @@ public class MathUtil {
     public static final BigDecimal PI = new BigDecimal(
             "3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679");
 
+    // https://hatter.ink/static/resource/muboard/?id=golden-ratio&version=latest&full=1
+    public static final BigDecimal PHI = new BigDecimal(
+            "1.6180339887498948482045868343656381177203091798057628621354486227052604628189024497072072041893911375"
+    );
+
     public static final BigDecimal LITTLE_NUMBER = new BigDecimal(
             "0.000000000000000000000000000000000000000001");