diff --git a/CMakeLists.txt b/CMakeLists.txt
index 146d616..e7d3ac8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -18,7 +18,12 @@ if(ENABLE_COVERAGE)
     append_coverage_compiler_flags()
 
     set(COVERAGE_GCOVR_EXCLUDES ${PROJECT_SOURCE_DIR}/lib ${PROJECT_BINARY_DIR})
+
+    include(ProcessorCount)
+    ProcessorCount(PROCESSOR_COUNT)
+
     set(command ctest -V -j ${PROCESSOR_COUNT})
+
     setup_target_for_coverage_gcovr_html(NAME coverage EXECUTABLE "${command}")
     setup_target_for_coverage_gcovr_xml(NAME coverage_xml EXECUTABLE "${command}")
     setup_target_for_coverage_gcovr_text(NAME coverage_text EXECUTABLE "${command}")