diff --git a/src/include/units/bits/unit_op.h b/src/include/units/bits/unit_op.h
new file mode 100644
index 00000000..a4a1527a
--- /dev/null
+++ b/src/include/units/bits/unit_op.h
@@ -0,0 +1,39 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#pragma once
+
+#include <units/unit.h>
+
+namespace units::detail {
+
+template<Dimension Dim1, Unit U1, Dimension Dim2, Unit U2,
+         typename Ratio1 = ratio_divide<typename U1::ratio, typename dimension_unit<Dim1>::ratio>,
+         typename Ratio2 = ratio_divide<typename U2::ratio, typename dimension_unit<Dim2>::ratio>>
+using unit_ratio_multiply = ratio_multiply<Ratio1, Ratio2>;
+
+template<Dimension Dim1, Unit U1, Dimension Dim2, Unit U2,
+         typename Ratio1 = ratio_divide<typename U1::ratio, typename dimension_unit<Dim1>::ratio>,
+         typename Ratio2 = ratio_divide<typename U2::ratio, typename dimension_unit<Dim2>::ratio>>
+using unit_ratio_divide = ratio_divide<Ratio1, Ratio2>;
+
+}  // namespace units::detail
diff --git a/src/include/units/quantity.h b/src/include/units/quantity.h
index 7241cc78..5f665e7f 100644
--- a/src/include/units/quantity.h
+++ b/src/include/units/quantity.h
@@ -24,10 +24,13 @@
 
 #include <units/bits/concepts.h>
 #include <units/bits/dimension_op.h>
+#include <units/bits/unit_op.h>
 #include <units/bits/unit_text.h>
+
 #if __GNUC__ >= 10
 #include <compare>
 #endif
+
 #include <limits>
 #include <ostream>
 
@@ -603,13 +606,11 @@ template<typename D1, typename U1, typename Rep1, typename D2, typename U2, type
 [[nodiscard]] constexpr Quantity AUTO operator*(const quantity<D1, U1, Rep1>& lhs, const quantity<D2, U2, Rep2>& rhs)
   requires (!equivalent_dim<D1, dim_invert<D2>>) &&  // TODO equivalent_derived_dim?
            (treat_as_floating_point<decltype(lhs.count() * rhs.count())> ||
-            (std::ratio_multiply<typename U1::ratio, typename U2::ratio>::den == 1)) &&
+            detail::unit_ratio_multiply<D1, U1, D2, U2>::den == 1) &&
            detail::basic_arithmetic<Rep1, Rep2>
 {
   using dim = dimension_multiply<D1, D2>;
-  using ratio1 = ratio_divide<typename U1::ratio, typename dimension_unit<D1>::ratio>;
-  using ratio2 = ratio_divide<typename U2::ratio, typename dimension_unit<D2>::ratio>;
-  using ratio = ratio_multiply<ratio_multiply<ratio1, ratio2>, typename dimension_unit<dim>::ratio>;
+  using ratio = ratio_multiply<detail::unit_ratio_multiply<D1, U1, D2, U2>, typename dimension_unit<dim>::ratio>;  ;
   using unit = downcast_unit<dim, ratio>;
   using common_rep = decltype(lhs.count() * rhs.count());
   using ret = quantity<dim, unit, common_rep>;
@@ -656,15 +657,13 @@ template<typename D1, typename U1, typename Rep1, typename D2, typename U2, type
 [[nodiscard]] constexpr Quantity AUTO operator/(const quantity<D1, U1, Rep1>& lhs, const quantity<D2, U2, Rep2>& rhs)
   requires detail::basic_arithmetic<Rep1, Rep2> && (!equivalent_dim<D1, D2>) &&  // TODO equivalent_derived_dim?
            (treat_as_floating_point<decltype(lhs.count() / rhs.count())> ||
-            (ratio_divide<typename U1::ratio, typename U2::ratio>::den == 1))
+            detail::unit_ratio_divide<D1, U1, D2, U2>::den == 1)
 {
   Expects(rhs.count() != 0);
 
   using common_rep = decltype(lhs.count() / rhs.count());
   using dim = dimension_divide<D1, D2>;
-  using ratio1 = ratio_divide<typename U1::ratio, typename dimension_unit<D1>::ratio>;
-  using ratio2 = ratio_divide<typename U2::ratio, typename dimension_unit<D2>::ratio>;
-  using ratio = ratio_multiply<ratio_divide<ratio1, ratio2>, typename dimension_unit<dim>::ratio>;
+  using ratio = ratio_multiply<detail::unit_ratio_divide<D1, U1, D2, U2>, typename dimension_unit<dim>::ratio>;
   using unit = downcast_unit<dim, ratio>;
   using ret = quantity<dim, unit, common_rep>;
   return ret(lhs.count() / rhs.count());