A worked example: ₹20L income, new regime, no TDS
An estimated ₹20,00,000 annual income under the new tax regime has a total tax liability of ₹1,92,400 — computed using the same slab-based formula as the income tax calculator. With no TDS deducted yet, that full amount becomes the advance tax due: ₹28,860 by June 15, ₹57,720 by September 15, ₹57,720 by December 15, and ₹48,100 by March 15.
The formula: cumulative 15/45/75/100% of net tax payable
The installment due dates track cumulative percentages of the year's net tax — 15% by June 15, 45% by September 15 (an additional 30%), 75% by December 15 (another 30%), and the remaining 25% by March 15. Each period's actual payment is the difference between that period's cumulative target and what's already been paid.
When TDS is already covering part of the liability
The same ₹20,00,000 income, but with ₹1,00,000 already deducted as TDS, cuts the net advance tax payable to ₹92,400 — exactly half of the no-TDS example — and each installment shrinks proportionally: ₹13,860, ₹27,720, ₹27,720, and ₹23,100.
Who actually needs to pay advance tax
Advance tax is required whenever total tax liability for the year, after TDS, exceeds ₹10,000 — this typically applies to freelancers, business owners, and anyone with significant income beyond a salary already subject to TDS, like capital gains or rental income.
What happens if an installment is missed
Missing or underpaying an installment can attract interest under Sections 234B and 234C of the Income Tax Act — a penalty this calculator doesn't compute, since it only estimates the installment schedule itself.