diff --git a/src/json.hpp b/src/json.hpp
index 6b1dc663..e8861926 100644
--- a/src/json.hpp
+++ b/src/json.hpp
@@ -58,13 +58,11 @@ SOFTWARE.
 
 // exclude unsupported compilers
 #if defined(__clang__)
-    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
-    #if CLANG_VERSION < 30400
+    #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
         #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
 #elif defined(__GNUC__)
-    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
-    #if GCC_VERSION < 40900
+    #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900
         #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
 #endif
diff --git a/src/json.hpp.re2c b/src/json.hpp.re2c
index 0eed0e6d..3a12a78d 100644
--- a/src/json.hpp.re2c
+++ b/src/json.hpp.re2c
@@ -58,13 +58,11 @@ SOFTWARE.
 
 // exclude unsupported compilers
 #if defined(__clang__)
-    #define CLANG_VERSION (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
-    #if CLANG_VERSION < 30400
+    #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400
         #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
 #elif defined(__GNUC__)
-    #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
-    #if GCC_VERSION < 40900
+    #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900
         #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers"
     #endif
 #endif