diff --git a/Userland/Libraries/LibM/math.cpp b/Userland/Libraries/LibM/math.cpp
index 653adb617788d5..53a7d522c47c0d 100644
--- a/Userland/Libraries/LibM/math.cpp
+++ b/Userland/Libraries/LibM/math.cpp
@@ -320,7 +320,7 @@ static FloatT internal_gamma(FloatT x) NOEXCEPT
     }
 
     // Stirling approximation
-    return sqrtl(2.0 * M_PI / static_cast<long double>(x)) * powl(static_cast<long double>(x) / M_E, static_cast<long double>(x));
+    return sqrtl(2.0 * M_PIl / static_cast<long double>(x)) * powl(static_cast<long double>(x) / M_El, static_cast<long double>(x));
 }
 
 extern "C" {
diff --git a/Userland/Libraries/LibM/math.h b/Userland/Libraries/LibM/math.h
index 8326d5af878600..a54e81ac639f6f 100644
--- a/Userland/Libraries/LibM/math.h
+++ b/Userland/Libraries/LibM/math.h
@@ -29,6 +29,20 @@ __BEGIN_DECLS
 #define NAN __builtin_nan("")
 #define MAXFLOAT FLT_MAX
 
+#define M_El 2.718281828459045235360287471352662498L
+#define M_LOG2El 1.442695040888963407359924681001892137L
+#define M_LOG10El 0.434294481903251827651128918916605082L
+#define M_LN2l 0.693147180559945309417232121458176568L
+#define M_LN10l 2.302585092994045684017991454684364208L
+#define M_PIl 3.141592653589793238462643383279502884L
+#define M_PI_2l 1.570796326794896619231321691639751442L
+#define M_PI_4l 0.785398163397448309615660845819875721L
+#define M_1_PIl 0.318309886183790671537767526745028724L
+#define M_2_PIl 0.636619772367581343075535053490057448L
+#define M_2_SQRTPIl 1.128379167095512573896158903121545172L
+#define M_SQRT2l 1.414213562373095048801688724209698079L
+#define M_SQRT1_2l 0.707106781186547524400844362104849039L
+
 #define M_E 2.7182818284590452354
 #define M_LOG2E 1.4426950408889634074
 #define M_LOG10E 0.43429448190325182765