Follow ₹10 lakh as it splits three ways.

9:30 am: the payment leaves

Castings supplier, monthly bill: ₹10,00,000 taxable plus 18% GST of ₹1,80,000, total ₹11,80,000. Your head of accounts signs the payment run at 9:30. What leaves your bank is not ₹11,80,000. Watch it split:

The new clerk watching this asks the question I love: where did the ₹1,000 go, and why does nobody at the GST portal care? The answer is the whole page. Two taxes, two governments inside one government, two tracks that share a voucher and nothing else.

The income-tax half

The ₹1,000 in the figure assumes 194Q treatment at a tenth of a percent on the ₹10 lakh purchase value, GST excluded. That exclusion is the detail desks get wrong most: TDS runs on the underlying value, not the GST-loaded total. Deduct on ₹11,80,000 and you have over-deducted ₹180 of somebody else's money, which buys you a reconciliation argument that survives for quarters.

Which section applies is a judgment call I will not make for you. Works contracts lean 194C. Goods purchases above the threshold lean 194Q. Mixed bills, part machining, part material, need a human who has read the contract. That human is your CA, and the right time to ask is before the payment run, not after the supplier calls about a short payment. The supplier's call always comes, because from their side ₹1,000 simply vanished, and your TDS certificate is the only proof it went somewhere legitimate.

A word on the supplier's side of the same rupee, because your relationship outlives the entry. That ₹1,000 sits in their Form 26AS as tax paid on their behalf, adjustable against their final liability. When you deposit late or file the TDS return with the wrong PAN, their 26AS breaks and your phone rings with a tone no narration can soften. Quarterly rhythm, then: deduct at payment, deposit by the due date, file the return, issue the certificate before they ask. Four beats, every quarter, no exceptions. Suppliers forgive short payments with certificates. They do not forgive ghost deductions.

The GST half, on its own track

Meanwhile the ₹1,80,000 moves on rails TDS never touches. Invoice posts, checksum passes, 2B shows the line, the 16(4) clock runs, credit lands. Nothing in that chain asks about your TDS deduction. Nothing in the TDS deposit asks about 2B. I have seen desks hold ITC hostage pending TDS clarity, as if the two tracks shared a signal. They do not. A clean GST invoice claims its credit on the GST timetable regardless of what income tax did at payment.

The reverse confusion is rarer but real: assuming a TDS deduction somehow proves the purchase for GST. It proves you paid and withheld. It says nothing about the supplier's GSTR-1, your 2B line, or the invoice's validity. Our section 16 page lists what actually proves those. TDS appears nowhere in it.

Step back and you see three clocks on one desk, and this is the image I want you to keep. TDS ticks quarterly: deduct at payment, deposit, return, certificate. GST ticks monthly: 2B, IMS, 3B. ITC ticks annually toward 16(4). Three rhythms, one AP team, and the voucher file is where they meet without colliding. Miss a quarterly beat and the supplier calls. Miss a monthly beat and 2B gaps. Miss the annual one and the credit is gone. Same desk, three metronomes, and the register keeps time for all of them.

The voucher that holds both

So the Tally entry for our morning carries all three destinations without mixing them: purchase ₹10,00,000 debit, ITC ₹1,80,000 debit, supplier credited ₹11,80,000, then TDS payable debited against the supplier for ₹1,000 with the net ₹11,79,000 paid. One voucher, two tax stories, each auditable on its own. The narration names the section applied, because six months later nobody remembers why this supplier lost ₹1,000 and the certificate file answers before the question is asked.

And our gate's place in this, stated once: it validates the GST invoice half. Checksum, fields, HSN, arithmetic, regime. TDS is computed at payment time on contract terms and thresholds the invoice alone does not carry. I will not stretch our product over a tax it cannot see.