diff --git a/makefile b/makefile
index b32fb66..d07b277 100644
--- a/makefile
+++ b/makefile
@@ -20,7 +20,7 @@ php_cs_fixer_fix: php-cs-fixer.phar
 	./php-cs-fixer.phar fix --config .php_cs src tests
 
 php_cs_fixer_check: php-cs-fixer.phar
-	./php-cs-fixer.phar fix --config .php_cs src tests --dry-run
+	./php-cs-fixer.phar fix --config .php_cs src tests --dry-run --diff --diff-format=udiff
 
 php-cs-fixer.phar:
 	wget https://github.com/FriendsOfPHP/PHP-CS-Fixer/releases/download/v2.16.6/php-cs-fixer.phar && chmod 777 php-cs-fixer.phar