India: the regime is chosen in the return, not on the payslip
An Indian salary arrives with tax already deducted. Your employer works out TDS each month on the salary it expects to pay you for the year, under the regime you told it about at the start of the year, and the bank deducts TDS from your deposit interest at a flat rate whatever your slab. The return, ITR-1 (Sahaj) for most salaried people or ITR-2 where there are larger capital gains or more than one house, settles the year: the tax your total income really bears against every rupee of TDS in Form 16 and Form 26AS.
Refunds come from three places. The bank's flat-rate TDS is often more than your slab asks for, and under the new regime it is refunded in full when the section 87A rebate clears your tax. Investments and rent you could not prove to your employer in time still count when you claim them in the return. And the regime itself can change: what you declared to your employer is for TDS only, so a salaried employee can choose the old regime in the return, for that year alone, if it is filed by the due date of 31 July. A return filed late can only use the new regime.
The new regime is the default, with a 75,000 rupee standard deduction and no tax on total income up to 12 lakh. Just above that, marginal relief cuts the tax to the income over 12 lakh. The old regime has narrower slabs and no such relief, but allows HRA, home-loan interest and the deductions for investments, NPS and health insurance. The calculator works your return under the regime you pick and shows the other beside it. Total income and the tax are each rounded to the nearest ten rupees.
From tax year 2026-27 the Income-tax Act 2025 applies. It renumbered every section and kept the amounts: section 80C is now section 123, 80D is section 126 and the rebate is section 156. The refund is paid after the Centralised Processing Centre processes the return, into a bank account pre-validated on the e-filing portal, once the return is e-verified.
Your employer deducted 97,500, the new regime's tax on 14,25,000 after the standard deduction, plus cess.
In the return you choose the old regime. From 15,00,000 come the HRA exemption of 1,80,000, the 50,000 standard deduction, 2,500 of professional tax and 2,00,000 of home-loan interest, then 1,50,000 of investments, 50,000 to NPS and 25,000 of health insurance: total income
8,42,500.
Tax on the old slabs is 81,000, plus 3,240 of cess: 84,240.
Refund: 13,260. Under the new regime the same return gives no refund.