Dear Bhavna,
This forum is primarily to provide guidance and suggestion to issues related to HR Functions. What you have asked is related to a mathematical equation. Though CTC calculation is also part of HR, but making reverse calculation is something different.
Now come to your points, the reverse calculation can be done, only if we have stepwise CTC Structure depend upon some % linked to previous component.
But you can easily calculate GROSS if you have all CTC components (basic pay structure, employer’s contributions, annual emoluments etc). Reverse calculation not required at all.
Other than GRISS, CTC have some extra components:-
1 Components which generally not paid on monthly basis (Bonus, Gratuity, Leaves etc).
2 Employer contributions towards social security and other legal and statutory compliances (PF, ESI, PT etc.).
3 Any other allowance which company pay annually, half yearly (LTA, Medical / Phone / Fuel Allowances etc).
Pls share specific figures of your CTC or Excel sheet, learned member will help you to calculate the GROSS.