Can candidates use calculators in the UPSC Civil Services Exam?

When it comes to using a calculator in the UPSC exam the rules differ, as if you are writing the first prelims exam then calculators are not allowed and the mains exam will allow you to use the scientific calculator for not the programmable one. So, it is necessary to be prepared to write the exam without the calculator which will help you in clearing the prelims and only after clearing the prelims will you be able to write the main exam.