Taxable income is the figure the slab rates are applied to. In the language of the Act it is total income: gross total income minus the deductions that the regime you are in still allows. On Finfod’s calculators the same idea is labelled net taxable income, after the standard deduction and whatever else the engine accepted.
It is not CTC. It is not the credit in your bank account. It is not the gain on shares that section 198 taxes at a special rate. Mixing those up is how a salary slip and a tax notice start to look as if they describe two different people.
The order is fixed. Start with salary. Take off the standard deduction, ₹75,000 in the new regime or ₹50,000 in the old regime, and only if the income is salary. In the old regime, take off HRA exemption while you are still inside the salary head. What remains, plus other heads, is gross total income. Then take off section 123 and the other deductions section 202 has not blocked. What remains is taxable income.
Section 156 looks at this figure when it decides whether the rebate applies. It does not reduce the figure. Surcharge looks at a wider total, including special-rate gains, when income is high. Cess looks at the tax, not at this income.
A worked example
Salary ₹15,00,000, marked as salary.
New regime. Standard deduction ₹75,000. Taxable income ₹14,25,000. Slab tax ₹93,750. Cess ₹3,750. Bill ₹97,500. A section 123 amount typed into the form does not change this taxable income, because section 202 does not allow it.
Old regime. Standard deduction ₹50,000. Section 123 claim ₹1,50,000. Taxable income ₹13,00,000. Bill ₹2,10,600.
Same salary, not marked as salary, new regime. There is no standard deduction. Taxable income stays ₹15,00,000 and the bill is ₹1,09,200. The income tax calculator is doing that switch when you tick salary. The in-hand salary calculator uses the taxable figure when it estimates what remains of CTC.
Mistakes people make
- Calling CTC the taxable income.
- Expecting the rebate to shrink the income. It shrinks the tax.
- Claiming old-regime deductions and watching the new-regime taxable income refuse to fall.
- Adding the ₹1,25,000 equity exemption into this figure. That exemption belongs to section 198, not to the slabs.
- Forgetting that a one-rupee change in taxable income can wipe the old-regime rebate. Salary of ₹5,50,001 produces a bill of ₹13,000.
The section
Total income is what the slabs and section 156 use. The standard deduction is section 19 (this was section 16(ia)). The big old-regime deduction after that is section 123 (this was section 80C). Section 202 (this was section 115BAC) is what blocks most of those later deductions. The regime guide compares the two taxable figures on one salary.
Questions
Is taxable income the same in both regimes?
Not on the same salary. ₹15,00,000 becomes ₹14,25,000 in the new regime and ₹13,00,000 in the old regime once the ₹1,50,000 section 123 cap is claimed. The bills are ₹97,500 and ₹2,10,600.
Does the rebate reduce taxable income?
No. The rebate reduces tax. Salary of ₹12,75,000 has taxable income of ₹12,00,000 and a bill of ₹0. The income figure did not become zero. The tax did.
Is a capital gain included in taxable income?
A slab gain, such as short-term gold, is included. A special-rate gain under section 196, 197 or 198 is taxed on its own. It can still affect surcharge, because surcharge looks at total income.
Sources
Figures checked 28 Oct 2026.