GST · SAC 998341 · FY 2026–27

SAC 998341: Geological and Geophysical Consulting

SAC 998341 (Geological and Geophysical Consulting) is taxed at 18% GST: 9% CGST + 9% SGST when you and your client are in the same state, 18% IGST when you are not, and 0% on exports under a Letter of Undertaking (LUT). Covers: Geological, geophysical and earth-sciences consulting.

Rate source: Notification 11/2017-Central Tax (Rate), Heading 9983

18%

Domestic
0% export (LUT)

Heading

9983 — professional & technical services

Domestic rate

18% (9+9 / IGST)

Export (LUT)

Reverse charge

No — forward charge

What falls under 998341

The CBIC Scheme of Classification defines 998341 as "Geological and geophysical consulting services" — geological, geophysical and related earth-sciences advice such as site investigations, environmental geology and seismology. Mineral exploration and evaluation carried out on your own account is a separate code, 998343; surface surveying and map-making is 998344.

Geological surveys

Geophysical site investigation

Environmental geology

Not this code — general engineering consulting and advisory work → 998331 · testing and analysis of materials, products and equipment → 998346

On the invoice

Invoice INV-0092SAC 998341

Geological surveys₹3,20,000

CGST @ 9% + SGST @ 9% (same state — else IGST 18%)+ ₹57,600

Amount due₹3,77,600

Same work for a foreign client under LUT: IGST 0%, with the zero-rating declaration on the face of the invoice.

A geological surveyor based in Ahmedabad (GJ, state code 24) runs a site survey for a Rajasthan mining company (RJ, state code 08). Rs. 3,20,000. Inter-state → IGST 18%.

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FAQ

Do I have to print the SAC code on my invoices?

Depends on turnover: up to Rs. 5 crore, the 4-digit SAC (9983) is enough on B2B invoices; above that, 6 digits are required. Printing the full 6-digit code (998341) everywhere is simplest and never wrong.

Under Rs. 20 lakh turnover — do I need to register and charge 18%?

Below Rs. 20 lakh aggregate turnover, registration is optional for pure service providers — you invoice without GST entirely. The Rs. 10 lakh threshold applies in only four special-category states (Manipur, Mizoram, Nagaland, Tripura), not the eleven usually listed online. Once registered, 18% applies to every domestic invoice regardless of turnover.

Wrong SAC code on past invoices — how bad is it?

If the rate charged was right, it is a clerical issue — fix it going forward. A wrong code with a wrong rate is the real problem; that needs a credit note and a corrected invoice. Mismatched SACs also cause GSTR-1 Table 12 disclosure issues and can trigger ITC audit queries at the client end.

Does SAC 998341 change under GST 2.0?

No. The September 2025 rate rationalisation reshuffled the goods slabs; professional and technical services stayed at the 18% standard rate, and export zero-rating under LUT is unchanged.

Notification reference: Notification 11/2017-CT(R) dated 28 June 2017 — the services rate table, at the serial for the code's heading (9982, 9983, 9985, 9992 or 9996 as applicable), as amended, including by Notification 15/2025-CT(R) (GST 2.0, from 22 September 2025).

For the CA reading this

The deadline sheet you already send, with your name on it

Every statutory date for the month — GST returns, advance tax, and the dates your client's own customers owe them: when the TDS they withheld must reach the department, and when the certificate is due. Add your firm's name and forward it as it stands. No signup, no email, nothing to accept.

Firm name (optional)Month

Download the image

The image is the one that travels on WhatsApp. Dates are statutory, not advice — the sheet says which rows bind whom.

Sources

Rates as notified for FY 2026–27 and can change. General information, not tax advice. Verify with your CA before you file.

Billing 998341 as a freelancer

Use Case

GST on Export of Services Without an LUT: What It Costs and What You Can Still Do

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GST Registration Limit for Freelancers: Have You Already Crossed It?

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Your Client Wants a GST Bill and You Have No GST Number

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