diff --git a/include/xo/unit/Quantity.hpp b/include/xo/unit/Quantity.hpp
index d24f2589..604664b2 100644
--- a/include/xo/unit/Quantity.hpp
+++ b/include/xo/unit/Quantity.hpp
@@ -242,6 +242,16 @@ namespace xo {
             return Quantity::divide(x, y);
         }
 
+        /** note: won't have constexpr result until c++26 (when ::sqrt(), ::pow() are constexpr)
+         **/
+        template <typename Quantity, typename Dimensionless>
+        requires quantity2_concept<Quantity> && std::is_arithmetic_v<Dimensionless>
+        constexpr auto
+        operator/ (const Quantity & x, Dimensionless y)
+        {
+            return x.divide_by(y);
+        }
+
         /** note: won't have constexpr result until c++26 (when ::sqrt(), ::pow() are constexpr)
          **/
         template <typename Quantity, typename Quantity2>