By Aditya GuptaAccounting and Finance EducatorLast reviewed August 22, 2026Practice: 108-topic study tool
Orientation

Tax is one calculation, interrupted several times

Indian income tax looks like a mass of unrelated rules and is really one calculation with interruptions. Add up income from every head. Subtract what the law allows. Apply the slabs. Add cess. Subtract what has already been collected on your behalf. Pay the difference, or claim it back. Every specific rule you have ever been confused by attaches to exactly one of those five steps.

The interruptions are what cause the confusion. TDS collects tax before you file, at a flat rate that is almost never your actual rate, which is why refunds and shortfalls both exist. Advance tax requires payment during the year rather than after it. Capital gains are taxed under their own rates and holding periods rather than at slab. And the choice between the old and new regimes changes which deductions exist at all.

GST is a separate system entirely and gets confused with income tax constantly. Income tax is charged on what you earn; GST is charged on what you sell, collected from your customer, and reduced by the tax you paid on your own purchases. If you run a business you deal with both, on different calendars, and conflating them is the most common compliance mistake made by small operators.

The Concept Map

The ten concepts, and where each one enters the calculation

The income tax chain first, then the collection mechanisms, then GST as a separate system.

Income Tax Basics

Five heads of income, the slab structure, cess, and the difference between gross income, total income and taxable income. Everything else attaches to this frame.

Deductions and Exemptions

What the law lets you subtract before the slabs apply. Section 80C, 80D, HRA and home loan interest are the large ones, and most are unavailable under the new regime.

Tax Planning

Arranging affairs legally so less tax is due. The distinction from avoidance and evasion matters, and most legitimate planning is about timing and instrument choice rather than clever structures.

Capital Gains Tax

Gains on assets taxed by their own rules. The holding period decides whether the gain is short or long term, and the rates differ by asset class rather than by your slab.

TDS and TCS

Tax collected at source, at a flat rate that rarely matches your actual liability. It is a credit against your final bill, not a final tax, which is why the reconciliation at filing matters.

Advance Tax

Paying during the year rather than after it, in four cumulative instalments, once the liability after TDS reaches ten thousand rupees. Missing an instalment costs interest, not a penalty.

ITR Filing

The annual return. Choosing the right form matters, and so does reconciling against Form 26AS and the annual information statement before submitting rather than after a notice.

GST Basics

A destination-based tax on supply, split into CGST, SGST and IGST. It is collected from your customer and set off against the tax you paid on inputs.

GST Returns and Compliance

The monthly and annual filing cycle, and the input tax credit matching that decides how much you actually pay. The calendar is unforgiving and the late fees accumulate daily.

Tax Audit

The threshold above which accounts must be examined by a chartered accountant. It is a reporting obligation rather than an accusation, and the presumptive schemes exist partly to avoid triggering it.

Test yourself on Taxation

Ten topics across income tax, TDS, capital gains and GST. Tax is largely rule recall, and the rules are easy to half-remember, which is where mistakes come from.

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Common Questions

Before you start

Old regime or new regime — how do I choose?+
Compute both and take the lower figure; there is no principle that decides it in the abstract. As a rough guide, the new regime usually wins where deductions are small, and the old regime usually wins where a home loan interest deduction, substantial HRA or a fully used 80C and 80D combine to a large total. Salaried taxpayers may choose afresh each year, so the answer can change as your circumstances do.
Why did TDS get deducted when I owe no tax?+
Because TDS is collected at a flat statutory rate on the transaction, without any knowledge of your total income, deductions or slab. A bank deducts on interest above a threshold and a client deducts on professional fees regardless of what your final liability turns out to be. If the amount collected exceeds what you owe, the excess is a refund claimed when you file, with interest paid by the department under Section 244A.
Is income tax the same as GST?+
No, and they share almost nothing except the word tax. Income tax is charged on what you earn, is paid by you, and is computed once a year on your total income. GST is charged on what you supply, is collected from your customer, is reduced by the tax you paid on your own inputs, and is filed monthly or quarterly. A business owner deals with both on separate calendars and under separate law.
Keep Going

The other nine Learn topics

Every domain follows the same shape: the concept map first, then the lessons that teach it, then the tools and scenarios that put it to work.

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