For salaried founders drawing ₹15–40 L, the new regime almost always wins — the standard deduction of ₹75,000 plus rebate under 87A make it hard to beat unless you have serious 80C + 24(b) + HRA claims stacked.
For founders drawing from an LLP or company as remuneration + interest on capital, the calculation flips. LLP remuneration is business income; the effective slab, self-employment deductions and ability to route certain expenses through the LLP means a projection is required — not a static rule.
Capital gains change the game. LTCG under Section 112A (equity) is taxed at 12.5% flat above ₹1.25 L regardless of regime — but the regime you pick still affects your slab-taxed component (salary, interest income, business income).
If you're actively parking capital in Section 54/54F reinvestment or claiming ESOP perquisite deferrals, the old regime is often still worth the paperwork. Model both. Always.