Tax · 8 min read
Form 16 explained, and what to check before you file
What Part A and Part B actually contain, how to cross-check them against Form 26AS and the AIS, and the mismatches that cause notices.
Krish Dalal
Founder and editor, PaisaExpert. Master's in Business Management, SP Jain School of Global Management, London. · Last updated 2026-09-04
Employers are required to issue it by 15 June for the financial year that ended the previous March. If you changed jobs, you need one from every employer, and the most common filing error in the country is a person who switched jobs mid year filing on the second Form 16 alone.
Part A: the tax trail
Part A is generated from the income tax department's own TRACES system, not typed up by your employer, which is what makes it worth something. It shows the employer's TAN, your PAN, the quarterly summary of tax deducted, and crucially the tax actually deposited with the government.
Part B: the salary breakup
Part B is prepared by the employer and is where the arithmetic of your tax lives: gross salary, the exemptions claimed under Section 10 such as HRA and LTA, the standard deduction, deductions under Chapter VI-A such as 80C and 80D, and the tax computed on what is left.
- Check that every declaration you actually submitted appears. Investment proofs handed in late are the usual casualty, and they simply will not be there.
- Check the regime. Part B is computed under whichever regime your employer had on file for you, and that is not necessarily the one that suits you. You can still choose the other when you file.
- Check HRA. If you paid rent but did not declare it in time, the exemption will be missing from Part B, and you can still claim it in the return itself.
Cross-check against 26AS and the AIS
Form 26AS is the department's own record of tax credited against your PAN from every source. The Annual Information Statement goes further and lists financial transactions reported by banks, mutual funds, registrars and others. Both are free on the income tax portal, and reading them takes ten minutes.
| Check | Where | What a mismatch means |
|---|---|---|
| TDS on salary | Form 16 Part A against 26AS | Employer has not deposited or has filed a wrong PAN |
| Interest income | AIS against your own records | Bank interest you forgot, which is taxable even if no TDS was cut |
| Share and fund sales | AIS against your broker statement | Capital gains you need to report |
| Other employer | 26AS shows a TAN you do not recognise | A previous employer's salary you have not included |
Most notices are not accusations of fraud. They are the department noticing that a number reported by a bank does not appear anywhere in your return. Reconciling before you file avoids nearly all of them.
If you changed jobs
- Collect a Form 16 from each employer for the year.
- Your new employer almost certainly gave you the basic exemption and deductions again, because they had no visibility of what the old one had already given. That means your combined tax is understated and you will owe the difference.
- Add both salaries, apply the exemptions once, and compute afresh. Do not simply add the two tax figures.
What to do next
- Download Form 26AS and the AIS from the income tax portal before you open your return.
- Line up Part A against 26AS quarter by quarter.
- Run both regimes rather than accepting the one on your Form 16.