Firstly, any person/assessee has to pay advance tax only if his estimated tax liability crosses a limit of Rs. 10,000.
Non-Corporate Assessees, such as Individuals, HUFs, Partnership Firms, AOPs, ets. have to pay such tax in 3 installments (i.e., by 15th September, 15th December and 15th March).
Corporate Assessees have to pay such tax in 4 installments (i.e. by 15th June, 15th September, 15th December and 15th March).
The balance/shortfall in any installment can be deposited after 15th March but upto 31st March.