diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog for `weierstrass-functions`
 
+## 0.1.3.1 - 2023-09-12
+
+Changed `kleinJ` to avoid possible float overflows.
+
+
 ## 0.1.3.0 - 2023-08-24
 
 Fixed some mistakes.
diff --git a/src/Math/Eisenstein.hs b/src/Math/Eisenstein.hs
--- a/src/Math/Eisenstein.hs
+++ b/src/Math/Eisenstein.hs
@@ -99,7 +99,8 @@
   lbd = lambda tau
   x = lbd * (1 - lbd)
   in
-  256 * ((1 - x) %^% 3) / (x %^% 2)
+  -- 256 * ((1 - x) %^% 3) / (x %^% 2)
+  256 * ((1/x - 1) %^% 2) * (1 - x)
   --eisensteinE4 tau %^% 3 / modularDiscriminant tau
 
 -- | Arithmetic-geometric mean
diff --git a/weierstrass-functions.cabal b/weierstrass-functions.cabal
--- a/weierstrass-functions.cabal
+++ b/weierstrass-functions.cabal
@@ -1,5 +1,5 @@
 name:                weierstrass-functions
-version:             0.1.3.0
+version:             0.1.3.1
 synopsis:            Weierstrass Elliptic Functions
 description:         Evaluation of Weierstrass elliptic functions and some related functions.
 homepage:            https://github.com/stla/weierstrass-functions#readme