Hi,
The main components in a compensation package are Basic, all Allowances, and all deductions.
Gross = Basic + all allowances (viz, HRA, TA, SPECIAL ALLOWANCES, CITY COMPENSATORY ALLOWANCES, etc.)
Net = Gross - all deductions (viz, Employee PF - 12%, employee ESI - 1.75%, P.TAX, etc.)
Other components are also included such as BONUS, OT, COMPENSATORY OFF, GRATUITY, MEDICAL REIMBURSEMENTS/MEDICLAIMS, LTA, INCENTIVES, etc.
Now, CTC = BASIC + ALL ALLOWANCES + EMPLOYER CONTRIBUTIONS (Viz PF - 12%, ESI - 4.75%, etc.)
Actually, there is no particular definition for CTC; it depends on the company's pay structure.
Few companies will include incentives in CTC, few companies will not.