diff --git a/conanfile.py b/conanfile.py
index 525926ba..b81bb763 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -84,11 +84,11 @@ class UnitsConan(ConanFile):
     def _configure_cmake(self, folder="src"):
         cmake = CMake(self)
         if self.options.downcast_mode == "off":
-            cmake.definitions["DOWNCAST_MODE"] = 0
+            cmake.definitions["UNITS_DOWNCAST_MODE"] = 0
         elif self.options.downcast_mode == "on":
-            cmake.definitions["DOWNCAST_MODE"] = 1
+            cmake.definitions["UNITS_DOWNCAST_MODE"] = 1
         elif self.options.downcast_mode == "auto":
-            cmake.definitions["DOWNCAST_MODE"] = 2
+            cmake.definitions["UNITS_DOWNCAST_MODE"] = 2
 
         if self._run_tests:
             # developer's mode (unit tests, examples, documentation, restrictive compilation warnings, ...)
diff --git a/docs/usage.rst b/docs/usage.rst
index 876ad4fd..8f67ba09 100644
--- a/docs/usage.rst
+++ b/docs/usage.rst
@@ -134,14 +134,14 @@ Specifies how :ref:`The Downcasting Facility` works:
 CMake Options
 ^^^^^^^^^^^^^
 
-DOWNCAST_MODE
-+++++++++++++
+UNITS_DOWNCAST_MODE
++++++++++++++++++++
 
 **Values**: ``OFF``/``ON``/``AUTO``
 
 **Defaulted to**: ``ON``
 
-Equivalent to `downcast`_.
+Equivalent to `downcast_mode`_.
 
 
 GENERATE_DOCS
diff --git a/example/hello_units.cpp b/example/hello_units.cpp
index 8a0f73ed..1c907134 100644
--- a/example/hello_units.cpp
+++ b/example/hello_units.cpp
@@ -37,7 +37,7 @@ int main()
   using namespace units::physical::si::literals;
   Speed auto v1 = avg_speed(220_q_km, 2_q_h);
   Speed auto v2 = avg_speed(si::length<si::international::mile>(140), si::time<si::hour>(2));
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
   Speed auto v3 = quantity_cast<si::dim_speed, si::metre_per_second>(v2);
 #else
   Speed auto v3 = quantity_cast<si::metre_per_second>(v2);
diff --git a/example/measurement.cpp b/example/measurement.cpp
index 76daef09..20269ac8 100644
--- a/example/measurement.cpp
+++ b/example/measurement.cpp
@@ -131,7 +131,7 @@ void example()
   const auto t = si::time<si::second, measurement<double>>(measurement(1.2, 0.1));
 
   const Speed auto v1 = a * t;
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
   std::cout << a << " * " << t << " = " << v1 << " = " << quantity_cast<si::dim_speed, si::kilometre_per_hour>(v1) << '\n';
 #else
   std::cout << a << " * " << t << " = " << v1 << " = " << quantity_cast<si::kilometre_per_hour>(v1) << '\n';
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b5d13abb..f79b2bad 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -27,8 +27,8 @@ project(mp-units
     LANGUAGES CXX
 )
 
-set(DOWNCAST_MODE ON CACHE STRING "Select downcasting mode")
-set_property(CACHE DOWNCAST_MODE PROPERTY STRINGS AUTO ON OFF)
+set(UNITS_DOWNCAST_MODE ON CACHE STRING "Select downcasting mode")
+set_property(CACHE UNITS_DOWNCAST_MODE PROPERTY STRINGS AUTO ON OFF)
 
 # set path to custom cmake modules
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
@@ -84,15 +84,15 @@ elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
     )
 endif()
 
-if(DOWNCAST_MODE STREQUAL "AUTO")
-    message(STATUS "Configuring DOWNCAST_MODE=AUTOMATIC")
-    target_compile_definitions(mp-units INTERFACE DOWNCAST_MODE=2)
-elseif(DOWNCAST_MODE)
-    message(STATUS "Configuring DOWNCAST_MODE=ON")
-    target_compile_definitions(mp-units INTERFACE DOWNCAST_MODE=1)
+if(UNITS_DOWNCAST_MODE STREQUAL "AUTO")
+    message(STATUS "Configuring UNITS_DOWNCAST_MODE=AUTOMATIC")
+    target_compile_definitions(mp-units INTERFACE UNITS_DOWNCAST_MODE=2)
+elseif(UNITS_DOWNCAST_MODE)
+    message(STATUS "Configuring UNITS_DOWNCAST_MODE=ON")
+    target_compile_definitions(mp-units INTERFACE UNITS_DOWNCAST_MODE=1)
 else()
-    message(STATUS "Configuring DOWNCAST_MODE=OFF")
-    target_compile_definitions(mp-units INTERFACE DOWNCAST_MODE=0)
+    message(STATUS "Configuring UNITS_DOWNCAST_MODE=OFF")
+    target_compile_definitions(mp-units INTERFACE UNITS_DOWNCAST_MODE=0)
 endif()
 
 add_library(mp-units::mp-units ALIAS mp-units)
diff --git a/src/include/units/bits/external/downcasting.h b/src/include/units/bits/external/downcasting.h
index ae5b068c..9d48af59 100644
--- a/src/include/units/bits/external/downcasting.h
+++ b/src/include/units/bits/external/downcasting.h
@@ -25,12 +25,12 @@
 #include <units/bits/external/hacks.h>
 #include <type_traits>
 
-#ifdef DOWNCAST_MODE
-#if DOWNCAST_MODE < 0 || DOWNCAST_MODE > 2
-#error "Invalid DOWNCAST_MODE value"
+#ifdef UNITS_DOWNCAST_MODE
+#if UNITS_DOWNCAST_MODE < 0 || UNITS_DOWNCAST_MODE > 2
+#error "Invalid UNITS_DOWNCAST_MODE value"
 #endif
 #else
-#define DOWNCAST_MODE 1
+#define UNITS_DOWNCAST_MODE 1
 #endif
 
 namespace units {
@@ -72,7 +72,7 @@ enum class downcast_mode {
 };
 
 
-template<typename Target, Downcastable T, downcast_mode mode = static_cast<downcast_mode>(DOWNCAST_MODE)>
+template<typename Target, Downcastable T, downcast_mode mode = static_cast<downcast_mode>(UNITS_DOWNCAST_MODE)>
 struct downcast_dispatch : std::conditional_t<mode == downcast_mode::off, T,
 #ifdef COMP_MSVC
                                               downcast_child<Target, T>> {};
diff --git a/src/include/units/bits/quantity_of.h b/src/include/units/bits/quantity_of.h
index 16adc768..04191d4d 100644
--- a/src/include/units/bits/quantity_of.h
+++ b/src/include/units/bits/quantity_of.h
@@ -28,7 +28,7 @@
 namespace units {
 
 // DimensionOfT
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 
 namespace detail {
 
@@ -53,7 +53,7 @@ concept EquivalentUnknownDimensionOfT = Dimension<Dim> && is_derived_from_specia
  */
 template<typename Dim, template<typename...> typename DimTemplate>
 concept DimensionOfT = Dimension<Dim> && (is_derived_from_specialization_of<Dim, DimTemplate>
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
                                           || EquivalentUnknownDimensionOfT<Dim, DimTemplate>
 #endif
 );
diff --git a/test/unit_test/runtime/fmt_test.cpp b/test/unit_test/runtime/fmt_test.cpp
index ff36fad5..683c0491 100644
--- a/test/unit_test/runtime/fmt_test.cpp
+++ b/test/unit_test/runtime/fmt_test.cpp
@@ -459,7 +459,7 @@ TEST_CASE("operator<< on a quantity", "[text][ostream][fmt]")
 
     SECTION("percents")
     {
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
       const auto q = quantity_cast<dim_one, percent>(15._q_m / 100._q_m);
 #else
       const auto q = quantity_cast<percent>(15._q_m / 100._q_m);
diff --git a/test/unit_test/static/dimensions_concepts_test.cpp b/test/unit_test/static/dimensions_concepts_test.cpp
index 298628ea..29e4bc1a 100644
--- a/test/unit_test/static/dimensions_concepts_test.cpp
+++ b/test/unit_test/static/dimensions_concepts_test.cpp
@@ -57,7 +57,7 @@ static_assert(!Area<si::time<si::second>>);
 
 static_assert(Volume<si::volume<si::cubic_metre>>);
 static_assert(!Volume<si::area<si::square_metre>>);
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 static_assert(Volume<quantity<unknown_dimension<exponent<si::dim_length, 3>>, unknown_coherent_unit>>);
 #endif
 
@@ -66,19 +66,19 @@ static_assert(!Speed<si::time<si::second>>);
 
 static_assert(Acceleration<si::acceleration<si::metre_per_second_sq>>);
 static_assert(!Acceleration<si::time<si::second>>);
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 static_assert(Acceleration<quantity<unknown_dimension<exponent<si::dim_length, 1>, exponent<si::dim_time, -2>>, unknown_coherent_unit>>);
 #endif
 
 static_assert(Force<si::force<si::newton>>);
 static_assert(!Force<si::time<si::second>>);
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 // static_assert(Force<quantity<unknown_dimension<exponent<si::dim_length, 1>, exponent<si::dim_time, -2>, exponent<si::dim_mass, 1>>, unknown_coherent_unit>>);
 #endif
 
 static_assert(Energy<si::energy<si::joule>>);
 static_assert(!Energy<si::time<si::second>>);
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 // static_assert(Energy<quantity<unknown_dimension<exponent<si::dim_mass, 1>, exponent<si::dim_length, 2>, exponent<si::dim_time, -3>>, unknown_coherent_unit>>);
 #endif
 
diff --git a/test/unit_test/static/quantity_test.cpp b/test/unit_test/static/quantity_test.cpp
index 85af6f2c..54783bc7 100644
--- a/test/unit_test/static/quantity_test.cpp
+++ b/test/unit_test/static/quantity_test.cpp
@@ -197,7 +197,7 @@ static_assert(q1.count() == 2);
 constexpr dimensionless<one> q2 = q1;
 static_assert(q2.count() == 2000);
 
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 static_assert(quantity_cast<dim_one, one>(q1).count() == 2000);
 #else
 static_assert(quantity_cast<one>(q1).count() == 2000);
@@ -310,7 +310,7 @@ static_assert(invalid_dimensionless_operations<int>);
 
 static_assert(compare<decltype(10_q_km / 5_q_km), quantity<dim_one, one, std::int64_t>>);
 
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 static_assert(quantity_cast<dim_one, percent>(50._q_m / 100._q_m).count() == 50);
 #else
 static_assert(quantity_cast<percent>(50._q_m / 100._q_m).count() == 50);
@@ -347,7 +347,7 @@ static_assert(compare<decltype(pow<2>(2_q_m)), decltype(4_q_m2)>);
 
 // downcasting
 
-#if DOWNCAST_MODE == 0
+#if UNITS_DOWNCAST_MODE == 0
 
 static_assert(std::is_same_v<decltype(10_q_m / 5_q_s), quantity<unknown_dimension<units::exponent<dim_length, 1>, units::exponent<dim_time, -1>>, scaled_unit<ratio(1), unknown_coherent_unit>, std::int64_t>>);
 static_assert(std::is_same_v<decltype(1_q_mm + 1_q_km), length<scaled_unit<ratio(1, 1, -3), metre>, std::int64_t>>);
diff --git a/test/unit_test/static/test_tools.h b/test/unit_test/static/test_tools.h
index c30d0aca..4d9dc1de 100644
--- a/test/unit_test/static/test_tools.h
+++ b/test/unit_test/static/test_tools.h
@@ -25,7 +25,7 @@
 #include "units/bits/equivalent.h"
 
 template<typename T, typename U>
-inline constexpr bool compare_impl = DOWNCAST_MODE != 0 ? std::is_same_v<T, U> : (std::is_same_v<T, U> || units::equivalent<T, U>);
+inline constexpr bool compare_impl = UNITS_DOWNCAST_MODE != 0 ? std::is_same_v<T, U> : (std::is_same_v<T, U> || units::equivalent<T, U>);
 
 template<typename T, typename U>
 inline constexpr bool compare = compare_impl<std::remove_cvref_t<T>, std::remove_cvref_t<U>>;