diff --git a/gnu/packages/maths.scm b/gnu/packages/maths.scm
index d9bc292..7cb40c4 100644
--- a/gnu/packages/maths.scm
+++ b/gnu/packages/maths.scm
@@ -103,6 +103,7 @@ (define-module (gnu packages maths)
   #:use-module (gnu packages bash)
   #:use-module (gnu packages bison)
   #:use-module (gnu packages boost)
+  #:use-module (gnu packages calendar)
   #:use-module (gnu packages check)
   #:use-module (gnu packages cmake)
   #:use-module (gnu packages compression)
@@ -124,6 +125,7 @@ (define-module (gnu packages maths)
   #:use-module (gnu packages ghostscript)
   #:use-module (gnu packages glib)
   #:use-module (gnu packages graphviz)
+  #:use-module (gnu packages groff)
   #:use-module (gnu packages gtk)
   #:use-module (gnu packages icu4c)
   #:use-module (gnu packages image)
@@ -172,6 +174,7 @@ (define-module (gnu packages maths)
   #:use-module (gnu packages tls)
   #:use-module (gnu packages version-control)
   #:use-module (gnu packages wxwidgets)
+  #:use-module (gnu packages xdisorg)
   #:use-module (gnu packages xml)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26))
@@ -455,6 +458,113 @@ (define-public dionysus
     (license license:gpl3+)
     (home-page "https://www.gnu.org/software/dionysus/")))
 
+(define-public dozenal
+  (let ((revision "1")
+        (commit "328bc03ad544179f2cccda36763358c4216f188e"))
+    (package
+      (name "dozenal")
+      (version (git-version "12010904-3" revision commit))
+      (source (origin
+                (method git-fetch)
+                (uri (git-reference
+                      (url "https://codeberg.org/dgoodmaniii/dozenal")
+                      (commit commit)))
+                (file-name (git-file-name name version))
+                (sha256
+                 (base32
+                  "0knwfwjqdv854l5ny7csdpvp7r0md6a2k43a1l2lkyw9k3cglpph"))))
+      (build-system gnu-build-system)
+      (arguments
+       (list
+             ;; Some test scripts are included, but no makefile-driven
+             ;; tests, and they are all quite manual to run and check
+             #:tests? #f
+             ;; Running with `make -j' causes the build to fail.
+             ;; This is likely because this project uses the
+             ;; "recursive make" structure, where each
+             ;; subdirectory contains its own make file, which is
+             ;; called by the top-level makefile.
+             #:parallel-build? #f
+             #:make-flags #~(list (string-append "prefix="
+                                                 #$output))
+             #:phases #~(modify-phases %standard-phases
+                          (add-after 'unpack 'chdir
+                            (lambda _
+                              (chdir "dozenal")))
+                          (add-after 'chdir 'patch-lua-references
+                            (lambda _
+                              (let ((lua-name (strip-store-file-name #$lua)))
+                                (substitute* '("dozcal/Makefile"
+                                               "dozlua/Makefile")
+                                  (("lua52")
+                                   (string-take lua-name
+                                                (string-rindex lua-name #\.)))))))
+                          (delete 'configure)
+                          (add-before 'install 'make-bin-dir
+                            (lambda _
+                              (mkdir-p (string-append #$output "/bin"))))
+                          (add-after 'install 'install-html-docs
+                            (lambda _
+                              (invoke "make"
+                                      (string-append "prefix="
+                                                     #$output) "installhtml")))
+                          (add-after 'install-html-docs 'split-outputs
+                            (lambda* (#:key inputs outputs #:allow-other-keys)
+                              (let* ((out (assoc-ref outputs "out"))
+                                     (gui (assoc-ref outputs "gui"))
+                                     (perl-tk (assoc-ref inputs "perl-tk"))
+                                     (perl-par (assoc-ref inputs "perl-par"))
+                                     (perl-dir "/lib/perl5/site-perl")
+                                     (ptk (string-append perl-tk perl-dir))
+                                     (pp (string-append perl-par perl-dir)))
+                                (for-each (lambda (prog)
+                                            (let ((orig (string-append out
+                                                         "/bin/" prog))
+                                                  (dst (string-append gui
+                                                                      "/bin/"
+                                                                      prog))
+                                                  (man-orig (string-append out
+                                                             "/share/man/man1/"
+                                                             prog ".1"))
+                                                  (man-dst (string-append gui
+                                                            "/share/man/man1/"
+                                                            prog ".1")))
+                                              (mkdir-p (dirname dst))
+                                              (copy-file orig dst)
+                                              (delete-file orig)
+                                              (mkdir-p (dirname man-dst))
+                                              (copy-file man-orig man-dst)
+                                              (delete-file man-orig)))
+                                          '("xdozdc" "gdozdc"))
+                                (wrap-program (string-append gui "/bin/"
+                                                             "gdozdc")
+                                              `("PERL5LIB" prefix
+                                                (,ptk ,pp))
+                                              `("PATH" prefix
+                                                (,(string-append out "/bin"))))))))))
+      (outputs '("out" "gui"))
+      (native-inputs (list groff pkg-config))
+      (inputs (list bash-minimal ;since wrap-program is used
+                    ncurses
+                    libhdate
+                    lua
+                    xforms))
+      (propagated-inputs (list perl perl-tk perl-par))
+      (synopsis
+       "Suite of dozenal programs, including converters, a calculator, and date
+program")
+      (description
+       "The dozenal suite is a set of programs designed to assist with
+working in the dozenal (also called \"duodecimal\" or \"base twelve\")
+system.  It includes number converters (dozenal-to-decimal and
+decimal-to-dozenal), an RPN calculator, a graphical calculator, a
+metric system converter (works with imperial, U.S. customary, SI
+metric, and the dozenal TGM), a pretty-printer for dozenal numbers, a
+date-and-time program, and a dozenal calendar programs, complete with
+events and to-dos.")
+      (home-page "https://codeberg.org/dgoodmaniii/dozenal")
+      (license license:gpl3+))))
+
 (define-public dsfmt
   (package
     (name "dsfmt")
