diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 0cc5b140..2132d71a 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -91,9 +91,10 @@ if(NOT ${projectPrefix}API_FREESTANDING)
                include/mp-units/bits/fmt.h
                include/mp-units/bits/requires_hosted.h
                include/mp-units/ext/format.h
+               include/mp-units/complex.h
+               include/mp-units/format.h
                include/mp-units/math.h
                include/mp-units/ostream.h
-               include/mp-units/format.h
                include/mp-units/random.h
     )
 endif()
diff --git a/src/core/include/mp-units/bits/core_gmf.h b/src/core/include/mp-units/bits/core_gmf.h
index 5566bc92..d3a44fcb 100644
--- a/src/core/include/mp-units/bits/core_gmf.h
+++ b/src/core/include/mp-units/bits/core_gmf.h
@@ -57,6 +57,7 @@
 #ifndef MP_UNITS_IMPORT_STD
 #include <chrono>
 #include <cmath>
+#include <complex>
 #include <locale>
 #include <ostream>
 #include <random>
diff --git a/src/core/include/mp-units/complex.h b/src/core/include/mp-units/complex.h
new file mode 100644
index 00000000..9f09c05f
--- /dev/null
+++ b/src/core/include/mp-units/complex.h
@@ -0,0 +1,43 @@
+// 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 <mp-units/bits/requires_hosted.h>
+//
+#include <mp-units/bits/module_macros.h>
+#include <mp-units/framework/customization_points.h>
+
+#ifndef MP_UNITS_IN_MODULE_INTERFACE
+#ifdef MP_UNITS_IMPORT_STD
+import std;
+#else
+#include <complex>
+#endif
+#endif
+
+namespace mp_units {
+
+template<typename T>
+constexpr bool is_complex<std::complex<T>> = true;
+
+}
diff --git a/src/core/include/mp-units/core.h b/src/core/include/mp-units/core.h
index 09ba3ac3..a99978f8 100644
--- a/src/core/include/mp-units/core.h
+++ b/src/core/include/mp-units/core.h
@@ -28,6 +28,7 @@
 #include <mp-units/framework.h>
 
 #if MP_UNITS_HOSTED
+#include <mp-units/complex.h>
 #include <mp-units/format.h>
 #include <mp-units/math.h>
 #include <mp-units/ostream.h>
diff --git a/test/static/concepts_test.cpp b/test/static/concepts_test.cpp
index c79e8851..83ecfa0a 100644
--- a/test/static/concepts_test.cpp
+++ b/test/static/concepts_test.cpp
@@ -23,6 +23,9 @@
 #include <mp-units/systems/isq/space_and_time.h>
 #include <mp-units/systems/natural.h>
 #include <mp-units/systems/si.h>
+#if MP_UNITS_HOSTED
+#include <mp-units/complex.h>
+#endif
 #ifdef MP_UNITS_IMPORT_STD
 import std;
 #else
@@ -35,12 +38,6 @@ import std;
 #endif
 #endif
 
-#if MP_UNITS_HOSTED
-template<typename T>
-constexpr bool mp_units::is_complex<std::complex<T>> = true;
-#endif
-
-
 namespace {
 
 using namespace mp_units;
diff --git a/test/static/quantity_test.cpp b/test/static/quantity_test.cpp
index 16c6ab46..ba34a160 100644
--- a/test/static/quantity_test.cpp
+++ b/test/static/quantity_test.cpp
@@ -29,6 +29,7 @@
 #include <mp-units/systems/isq/space_and_time.h>
 #include <mp-units/systems/si.h>
 #if MP_UNITS_HOSTED
+#include <mp-units/complex.h>
 #include <mp-units/math.h>
 #endif
 #ifdef MP_UNITS_IMPORT_STD
@@ -45,11 +46,6 @@ import std;
 #endif
 #endif
 
-#if MP_UNITS_HOSTED
-template<typename T>
-constexpr bool mp_units::is_complex<std::complex<T>> = true;
-#endif
-
 template<>
 constexpr bool mp_units::is_vector<int> = true;