No, you can claim tax exemption only on the lowest of the following amounts
INR 20 lakhs
The eligible amount using the specified formula for calculating gratuity
The actual amount of gratuity received from the employer
Any gratuity received in excess of the afore-mentioned amount would be subject to tax at your income tax slab rates. However, if you are a Government employee, the whole amount of gratuity that you receive would be tax-free in your hands.