India GST Compliance Checker
Four independent checks for common India GST paperwork mistakes, all running locally in your browser: a GSTIN check-digit validator implementing GSTN's official character-set checksum algorithm (not just a regex), an e-invoice (IRN) applicability helper against the current notified aggregate-turnover threshold, an HSN/SAC code format checker (4/6/8-digit numeric for HSN, 6-digit for SAC), and a CGST+SGST=IGST math consistency check for a line item. None of this queries the live GST Network. The GSTIN check confirms the number is internally consistent, not that it is currently active or belongs to the business you think it does, and the e-invoice threshold is a government-notified figure that has been lowered several times; it's shown editable with an 'as of' date rather than baked in silently. Use this to catch typos and arithmetic mistakes before filing, not as a substitute for a GSTN lookup or a chartered accountant.
Reviewed by Riccardo Dal Cero, Economist & Consultant · Last updated September 27, 2026
How it works
- 1
Paste one or more GSTINs to run them through the real 15-character check-digit algorithm and see whether the format and checksum are internally consistent.
- 2
Enter your aggregate annual turnover to check it against the current e-invoicing (IRN) mandate threshold, which is editable and labeled with the date it was last verified.
- 3
Enter an HSN or SAC code to check it matches the expected digit-length format for that code type.
- 4
Enter CGST, SGST, and IGST amounts for a line item to check they're arithmetically consistent (CGST + SGST should equal IGST).
A real checksum, not a regex
Many GSTIN 'validators' online only check the format with a regular expression, which happily accepts a number with a completely wrong check digit. This tool implements the character-set-and-factor checksum algorithm GSTN uses to generate the 15th character, so it catches transposed digits and mistyped PAN segments that a format-only check would miss.
Why the e-invoice threshold isn't hardcoded quietly
India's e-invoicing mandate turnover threshold has moved down repeatedly since its 2020 introduction, from INR 500 crore originally to INR 5 crore currently, with further reductions publicly discussed. A tool that silently assumes one number will eventually give a wrong answer to someone whose obligation changed, so the threshold here is shown with its verification date and left editable.
Format and math checks, not tax advice
Every check in this tool is either a deterministic checksum, a format-length rule, or plain addition. None of it substitutes for a GSTN portal lookup, a review by a chartered accountant, or confirmation of the officially notified rate for your specific goods or services. Treat a clean result here as 'nothing obviously wrong', not as final sign-off.
Frequently asked questions
Does a passing GSTIN check mean the business is real and registered?
No. This tool never queries the GST Network or any live registry. It only verifies that the 15th character is the mathematically correct checksum for the first 14 characters, per GSTN's published algorithm. A GSTIN can pass this check and still be inactive, cancelled, or fabricated by combining a valid PAN pattern with a computed checksum. For a live status check, use the official GST portal.
Is the GSTIN checksum algorithm itself likely to change?
No. Unlike the e-invoice threshold, the check-digit algorithm is a fixed mathematical formula (in the ISO 7064 MOD 37,36 family) built into how GSTINs are generated, so it's safe to treat as stable rather than something that needs periodic re-verification.
Is the e-invoice threshold shown here guaranteed current?
It reflects the aggregate turnover threshold (INR 5 crore) verified via search as of 2026-09-27, in effect since 1 August 2023. This figure has been lowered by government notification multiple times since 2020, and a further reduction has been publicly discussed. The threshold field is editable. Always confirm the latest notification on the GST portal before treating a result as final, and remember the obligation continues once triggered in any year even if turnover later drops.
What's the difference between HSN and SAC codes, and what does this tool check?
HSN codes classify goods and can be reported at 4, 6, or 8 digits depending on your turnover tier; SAC codes classify services and are always 6 digits. This tool only checks that the code you entered has a plausible digit-length format for the type you selected. It does not verify the code exists in the official HSN/SAC master list or matches your actual product or service.
What does the CGST+SGST=IGST check actually verify?
For an intra-state supply, CGST and SGST are charged instead of IGST and together should equal what IGST would have been for the equivalent inter-state supply. This tool just checks that the three numbers you typed in add up consistently. It does not know or verify the officially notified GST rate for your specific good or service.
Can I check many GSTINs at once?
Yes, paste them one per line or comma-separated, and each is checked independently.
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