The rule in one paragraph
If your total tax for the year will be more than ₹10,000 after TDS, you have to pay it in four instalments during the year rather than in one go when you file. This is section 211 of the Income Tax Act, and it applies to freelance and business income, which is what brand deals are.
The four dates
Each is a cumulative percentage of your total expected tax for the year, not a quarter of it. By 15 September you should have paid 45% in total, not 45% of what is left.
- 15 June: 15% of the year's tax
- 15 September: 45% cumulative
- 15 December: 75% cumulative
- 15 March: 100%
The financial year runs April to March, so 15 March is the last date for the year that began the previous April.
What counts as your income
What actually reached your account, minus what the work cost you. Camera gear, editing, props you bought for a shoot, the fee you pay an editor, software subscriptions, travel for a brand shoot: all of it comes off before tax is calculated. Most creators pay more tax than they need to because they never wrote these down.
Money a brand still owes you is not income yet. Advance tax is on what has arrived.
TDS is already part of this
Most brands deduct 10% TDS under section 194J before paying you. That is not a separate tax, it is an advance payment of the same tax, made on your behalf. Subtract it from what you owe. If your brands deduct enough, you may owe no advance tax at all.
If you miss a date
Interest under sections 234B and 234C, at 1% a month on the shortfall. It is not a penalty and nobody comes after you, which is precisely why it is easy to ignore until it has been running for eight months.
The honest advice
Set aside roughly a third of every payment as it arrives, in a separate account you do not touch. Then the four dates are a transfer rather than a scramble. The exact rate depends on your slab and your deductions, and a chartered accountant is worth the fee the first year.