diff --git a/Makefile.am b/Makefile.am
index ab78f268..b3495aed 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -124,6 +124,8 @@ UTIL_FILES   =		\
     random.ipp		\
     range.cpp		\
     range.hpp		\
+    rational.cpp	\
+    rational.hpp	\
     region.cpp		\
     region.hpp		\
     si.cpp		\
diff --git a/rational.cpp b/rational.cpp
new file mode 100644
index 00000000..351dfac9
--- /dev/null
+++ b/rational.cpp
@@ -0,0 +1,59 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2014 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "rational.hpp"
+
+#include <cstdint>
+
+using util::rational;
+
+
+//-----------------------------------------------------------------------------
+template <typename T>
+rational<T>::rational (T _n, T _d):
+    n (_n),
+    d (_d)
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+template <typename T>
+bool
+rational<T>::operator== (const rational<T> &rhs) {
+    return rhs.n == n && rhs.d == d;
+}
+
+
+//-----------------------------------------------------------------------------
+template <typename T>
+rational<T>::operator float (void) const {
+    return static_cast<float> (n) / d;
+}
+
+
+//-----------------------------------------------------------------------------
+template <typename T>
+rational<T>::operator double (void) const {
+    return static_cast<double> (n) / d;
+}
+
+
+//-----------------------------------------------------------------------------
+template struct rational<uint32_t>;
+template struct rational<int32_t>;
diff --git a/rational.hpp b/rational.hpp
new file mode 100644
index 00000000..0ccf141b
--- /dev/null
+++ b/rational.hpp
@@ -0,0 +1,39 @@
+/*
+ * This file is part of libgim.
+ *
+ * libgim is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * libgim is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2014 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef __UTIL_RATIONAL_HPP
+#define __UTIL_RATIONAL_HPP
+
+namespace util {
+    template <typename T>
+    struct rational {
+        rational (T _n, T _d);
+        rational& operator=  (const rational&) = default;
+
+        bool operator== (const rational&);
+
+        explicit operator float  (void) const;
+        explicit operator double (void) const;
+
+        T n;
+        T d;
+    };
+}
+
+#endif