diff --git a/src/main/metric_tools.F90 b/src/main/metric_tools.f90
similarity index 100%
rename from src/main/metric_tools.F90
rename to src/main/metric_tools.f90
diff --git a/src/main/utils_gr.F90 b/src/main/utils_gr.f90
similarity index 100%
rename from src/main/utils_gr.F90
rename to src/main/utils_gr.f90