28/08/2026
How employers calculate monthly TDS on salary, declaration form, adjustments
Why Does TDS on Salary Change Every Month?
A lot of salaried employees notice their monthly TDS isn't the same number each month. Some months it spikes. Sometimes December and March see big deductions. Here's why.
Your employer calculates TDS on salary under Section 192 by projecting your annual income at the start of the year. Let's say your CTC is Rs 12 lakh. They estimate Rs 12 lakh as your full-year income, calculate the tax on it, and divide by 12. That gives your monthly TDS.
But your actual income changes. Bonus in October? Employer recalculates the annual projection and adjusts the remaining months to ensure the full-year TDS is correct.
How your declarations matter: At the start of the year, you submit Form 12BB declaring deductions (HRA, home loan interest, Section 80C investments). Your employer factors these in. If you declared a Rs 1.5 lakh 80C investment but haven't made it by February, the employer will increase TDS in February-March to make up the difference.
What to submit before March:
Investment proofs (LIC receipts, ELSS statement, PPF passbook)
Rent receipts if claiming HRA
Home loan statement for Section 24B interest
NPS contribution under 80CCD(1B)
If you over-declare and your actual investments are lower, you'll face excess TDS that has to be refunded via ITR , which takes 6-8 months. If you under-declare, you pay more TDS than you needed to.
Full Section 192 calculation methodology: [TDS on salary Section 192 guide](https://taxgarden.in/blog/tds-on-salary-section-192-392-employer-guide-india)
