diff --git a/src/core/include/units/reference.h b/src/core/include/units/reference.h
index 31cf14c9..6524b84a 100644
--- a/src/core/include/units/reference.h
+++ b/src/core/include/units/reference.h
@@ -101,6 +101,12 @@ template<Representation Rep, Reference R>
 
 void /*Use `q * (1 * r)` rather than `q * r`.*/ operator*(Quantity auto, Reference auto) = delete;
 
+template<Reference R1, Reference R2>
+[[nodiscard]] consteval bool operator==(R1, R2)
+{
+  return R1::dimension == R2::dimension && R1::unit == R2::unit;
+}
+
 template<Reference R1, Reference R2>
 [[nodiscard]] consteval bool interconvertible(R1, R2)
 {