Hi there,
Let's assume your CTC per annum is 200,000. If you divide this by 12, you will get your Monthly CTC, which means 200,000/12 = 16,666 per month.
Next, you can consider either 40% or 50% of this CTC as your Basic salary. For example, if you take 50% of 16,666, the calculation would be 16,666 * 50/100 = 8,333 as your monthly Basic salary.
I hope this clarifies the calculation process for you. Let me know if you need further assistance or information.