diff --git a/pkgs/development/ocaml-modules/farith/default.nix b/pkgs/development/ocaml-modules/farith/default.nix
new file mode 100644
index 000000000000..3840f7881fc1
--- /dev/null
+++ b/pkgs/development/ocaml-modules/farith/default.nix
@@ -0,0 +1,38 @@
+{
+  lib,
+  buildDunePackage,
+  fetchFromGitLab,
+  ppx_deriving,
+  ppx_hash,
+  zarith,
+}:
+
+buildDunePackage rec {
+  pname = "farith";
+  version = "0.1";
+
+  minimalOCamlVersion = "4.10";
+
+  src = fetchFromGitLab {
+    domain = "git.frama-c.com";
+    owner = "pub";
+    repo = "farith";
+    tag = version;
+    hash = "sha256-9TGKeL3DXKEf2RLpkjOTC8aDQeLKSM9QUIiSkFCQW+8=";
+  };
+
+  propagatedBuildInputs = [
+    ppx_deriving
+    ppx_hash
+    zarith
+  ];
+
+  doCheck = true;
+
+  meta = {
+    description = "Modelisation of base 2 floating points with arbitrary exponent and mantisse size.";
+    homepage = "https://git.frama-c.com/pub/farith";
+    license = lib.licenses.lgpl2Only;
+    maintainers = with lib.maintainers; [ ethancedwards8 ];
+  };
+}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 46ff0e6ff27f..ccbe15b7ee9b 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -610,6 +610,8 @@ let
 
         farfadet = callPackage ../development/ocaml-modules/farfadet { };
 
+        farith = callPackage ../development/ocaml-modules/farith { };
+
         fdkaac = callPackage ../development/ocaml-modules/fdkaac { };
 
         ff = callPackage ../development/ocaml-modules/ff { };