There is no fixed number that be commonly used. It depends on your lifestyle and future needs. Key factors to consider for calculating include:

• Current expenses
• Expected retirement lifestyle
• Inflation (to project future expenses based on current costs)
• Goals for the retirement years (monthly expenses, travel, philanthropy, etc.)
• Years left to plan for retirement
• Healthcare costs
• Contingency fund needs
• Existing investments (Mutual Fund, PPF, pension funds, etc.)

A retirement plan should be reviewed regularly as your lifestyle changes. Starting early allows you to harness the power of compounding and create a sizeable corpus. Consulting an expert ensures your plan covers multiple scenarios and you do not exhaust your retirement corpus.