How monthly TDS on salary is worked out
Last updated: 2026-08-14
Tax deducted at source on salary does not work the way many people assume. Your employer does not apply a rate to each month's pay. Under Section 192 they estimate your tax for the whole financial year, subtract what has already been deducted, and divide the balance across the months they still expect to pay you.
That one design decision explains almost every surprise on an Indian payslip.
The calculation, in order
- Project your salary for the full financial year
- Apply exemptions and deductions you have declared
- Compute the tax on that annual figure, including cess and any surcharge
- Subtract tax already deducted this year
- Divide what is left by the months remaining
Because step five divides by remaining months rather than twelve, joining or switching mid-year concentrates the same annual tax into fewer payslips.
The mid-year job change
This is where most large surprises come from. Your new employer must withhold on your combined salary from both employers for the year. If you do not declare the previous employer's salary, the new employer applies the basic exemption and your deductions a second time, under-deducts all year, and leaves you with a bill at filing.
| Line | Amount |
|---|---|
| Tax for the whole year on combined salary | Rs 3,91,654 |
| Already deducted by the previous employer | −Rs 50,000 |
| Balance to collect | Rs 3,41,654 |
| Months remaining | 6 |
| Monthly TDS from here | Rs 56,942 |
Declare the previous salary using Form 12B and your new employer collects the right amount steadily. Skip it and the correction arrives all at once at filing.
Why the bonus month looks wrong
Tax on variable pay is withheld in the month the bonus is actually paid, not spread across the year. That payslip therefore shows a much larger deduction than the other eleven, alongside a much larger gross. Nothing has gone wrong; the deduction is simply landing where the income landed.
Several states add a second wrinkle at the end of the year. Maharashtra, Karnataka and Madhya Pradesh charge a higher professional tax in the final month so the annual total lands exactly on the statutory ceiling, which makes the last payslip of the year slightly smaller than the previous eleven.
Common questions
Why did my TDS jump in January?
Usually one of three things: a bonus was paid, a declared investment was not evidenced by the proof deadline and has been withdrawn from the projection, or your employer has recalculated after a salary revision.
Can I ask my employer to deduct less?
Only by declaring deductions you are genuinely entitled to, and evidencing them. Your employer must deduct on the projection they hold; they cannot deduct less on request.
What if too much has been deducted?
You claim it back as a refund when you file. Over-deduction is a cash-flow problem rather than a permanent loss.
How do I check my employer has it right?
Enter the amounts printed on your slip into the salary slip TDS checker. It compares each line against what the rules produce for your structure and names the biggest gap.
Related: CTC versus in-hand salary and choosing between the two tax regimes.
What the months remaining do to your deduction
The same annual tax collected over fewer months produces a larger deduction each month. This is the arithmetic behind almost every mid-year surprise.
| Months remaining | Monthly TDS | Against a full year |
|---|---|---|
| 12 | Rs 25,000 | Baseline |
| 9 | Rs 33,333 | +33% |
| 6 | Rs 50,000 | +100% |
| 3 | Rs 1,00,000 | +300% |
Nothing about the tax changed in any row. Only the number of payslips available to collect it did, which is why joining in October feels so different from joining in April.
Related reading
The rest of this series, and the calculators that let you run the idea on your own numbers.
More india salary and tax guides
Try it with your figures
See also all guides, every calculator, and the calculation methodology behind these estimates.