Do we need to pay stamp duty for gifting a flat?

Yes , the stamp duty of 3% is payable and tax on gift deed of property is applicable as follows:

The price of all gifts a person receives throughout a year is totally exempt under income tax legislation, as long as the final value of these gifts doesn't really surpass Rs 50,000 per year. If the total value of all gifts received reaches Rs 50,000, the total value of all gifts received becomes taxable. Gifts among two family members are treated favorably by income tax legislation. The transfer of any asset (movable or immovable) to such a selected family is completely tax-free in the recipient's hands, with no maximum limit. This answers your query about is stamp duty payable if a property is gifted.