diff --git a/src/core/include/units/magnitude.h b/src/core/include/units/magnitude.h
index d65c9ad1..7656a348 100644
--- a/src/core/include/units/magnitude.h
+++ b/src/core/include/units/magnitude.h
@@ -517,16 +517,14 @@ constexpr auto numerator(magnitude<BPs...>)
 
 constexpr auto denominator(Magnitude auto m) { return numerator(pow<-1>(m)); }
 
-// Implementation of implicit conversion to ratio goes here, because it needs `numerator()` and `denominator()`.
-template<BasePower auto... BPs>
-  requires detail::is_base_power_pack_valid<BPs...>
-constexpr magnitude<BPs...>::operator ratio() const
+// Implementation of conversion to ratio goes here, because it needs `numerator()` and `denominator()`.
+constexpr ratio as_ratio(Magnitude auto m)
 {
-  static_assert(is_rational(magnitude<BPs...>{}));
+  static_assert(is_rational(m));
 
   return ratio{
-    get_value<std::intmax_t>(numerator(*this)),
-    get_value<std::intmax_t>(denominator(*this)),
+    get_value<std::intmax_t>(numerator(m)),
+    get_value<std::intmax_t>(denominator(m)),
   };
 }
 
diff --git a/test/unit_test/runtime/magnitude_test.cpp b/test/unit_test/runtime/magnitude_test.cpp
index 038aff8a..22a3dd4b 100644
--- a/test/unit_test/runtime/magnitude_test.cpp
+++ b/test/unit_test/runtime/magnitude_test.cpp
@@ -374,9 +374,9 @@ TEST_CASE("Constructing ratio from rational magnitude")
     check_ratio_round_trip_is_identity<ratio{5, 8}>();
   }
 
-  SECTION("Rational magnitude implicitly converts to ratio")
+  SECTION("Rational magnitude converts to ratio")
   {
-    constexpr ratio r = as_magnitude<ratio{22, 7}>();
+    constexpr ratio r = as_ratio(as_magnitude<ratio{22, 7}>());
     CHECK(r == ratio{22, 7});
   }