GSTIN Validator & Decoder
Paste any 15-character GST number. We'll verify the format and checksum and break it down into the state, embedded PAN, entity type, and entity number — all in your browser, nothing uploaded.
- Look at any GST invoice — the issuer's GSTIN is in the header.
- Log in to gst.gov.in — your registered businesses' GSTINs are listed there.
- Check your GST Registration Certificate (Form GST REG-06).
- Format: 29AAFCM7878E1ZX — state code (2) + PAN (10) + entity # (1) + Z + checksum.
The validator runs entirely in your browser. Pulsyr never sees the GSTINs you check — verifiable in DevTools → Network tab (zero requests during validation).
What is a GSTIN?
GSTIN stands for Goods and Services Tax Identification Number. It's the 15-character alphanumeric code issued by India's GST regime to every registered taxpayer. Every GST-compliant invoice carries the issuer's GSTIN. Every input-tax-credit claim references it. Every GSTR-1 / GSTR-3B filing is keyed by it.
The 15 characters break down like this:
State code (2 digits)— official 2-digit code for the state of registration. 27 = Maharashtra, 29 = Karnataka, 33 = Tamil Nadu, 24 = Gujarat, 09 = Uttar Pradesh, 07 = Delhi, 19 = West Bengal, and so on. The same business operating across multiple states gets multiple GSTINs (one per state) — but they'll all share the same embedded PAN.
PAN (10 chars) — the entity's Permanent Account Number, embedded directly. The 4th character of the PAN tells you what kind of entity it is: Proprietor, Company, Firm, HUF, AOP, Trust, BOI, Local Authority, Juridical Person, Government.
Entity number in state (1 char) — usually 1, but if a single PAN registers multiple times in the same state (different verticals or business divisions), it becomes 2, 3, etc., up to letters once digits run out.
Reserved (Z)— always literally the letter Z. Reserved for future use; if it's anything else, the GSTIN is malformed.
Checksum (1 char)— calculated from the previous 14 using GSTN's base-36 modulus algorithm. Catches transcription errors and made-up GSTINs immediately.
When you actually need to validate a GSTIN
Onboarding a new vendor
Before you set up a vendor in your accounting software, validate their GSTIN. Catches typos and made-up codes that would later fail your input-tax-credit claim during GST filing.
Issuing your first invoice to a B2B customer
GST-compliant invoices need the recipient's correct GSTIN. A wrong checksum here means the invoice can be rejected during the customer's GSTR-2A reconciliation.
Bulk verification of an existing vendor list
If you've inherited a vendor master file, run every GSTIN through structural validation as a first-pass cleanup. Anything that fails the checksum is a known-bad row to fix before filing.
Customer KYC / due diligence
For B2B leads claiming to be businesses, a quick GSTIN check confirms they're at least in the GST register. Combined with a portal lookup, you can verify activation status.
Spotting fraudulent invoices
Fake invoices sometimes carry fabricated GSTINs that look real but fail the checksum. Validation flags them in seconds.
Decoding multi-state vendors
If a vendor operates across states, each branch has its own GSTIN. Decoding the state code instantly tells you which registration corresponds to which delivery point.
PAN entity codes (4th char of the embedded PAN)
| Letter | Entity type |
|---|---|
| A | Association of Persons (AOP) |
| B | Body of Individuals (BOI) |
| C | Company |
| F | Firm / LLP |
| G | Government |
| H | Hindu Undivided Family (HUF) |
| J | Artificial Juridical Person |
| L | Local Authority |
| P | Person / Proprietor (Individual) |
| T | Trust |
Frequently asked questions
What is a GSTIN?▼
GSTIN stands for Goods and Services Tax Identification Number. It's a 15-character alphanumeric code issued to every business registered under India's GST regime. The Central Board of Indirect Taxes (CBIC) maintains the official register; you can verify any GSTIN at gst.gov.in.
What does each part of a GSTIN mean?▼
Positions 1-2: state code (e.g. 27 = Maharashtra, 29 = Karnataka). Positions 3-12: the entity's PAN. Position 13: entity number for that PAN within the state (1, 2, 3… for multiple registrations of the same PAN in the same state). Position 14: always Z (reserved for future use). Position 15: checksum digit calculated from the previous 14.
How is GSTIN different from PAN?▼
PAN identifies a tax entity (a person, company, firm, etc.) for income tax. GSTIN identifies a GST registration of that entity in a specific state — so the same business operating across multiple states gets multiple GSTINs but only one PAN. The PAN is embedded inside positions 3-12 of every GSTIN issued to that entity.
Can two businesses have the same GSTIN?▼
No. GSTINs are globally unique within India's GST system. Even if two entities share a state and an entity-type prefix, their PAN segment differs, making the full 15-character code unique.
Why does my GSTIN start with 27 / 29 / etc.?▼
The first two digits are the state code per India's official GST state-code list. 07 = Delhi, 09 = UP, 19 = West Bengal, 24 = Gujarat, 27 = Maharashtra, 29 = Karnataka, 33 = Tamil Nadu, 36 = Telangana, 37 = Andhra Pradesh. The state where your business is registered determines this prefix.
How do I verify a vendor's GSTIN before paying them?▼
Three quick steps: (1) Run it through this tool — it confirms the format and the checksum, which catches typos and made-up codes instantly. (2) Cross-check the embedded PAN against any other PAN they've shared with you. (3) For high-value vendors, look it up on gst.gov.in's official 'Search Taxpayer' tool — that's the source-of-truth and confirms the registration is active.
What does the entity-type letter (4th char of the embedded PAN) tell me?▼
P = Proprietor / Individual, C = Company, F = Firm / LLP, H = HUF, A = Association of Persons, T = Trust, B = Body of Individuals, L = Local Authority, J = Artificial Juridical Person, G = Government. So a GSTIN with C in position 6 (which is the 4th char of the embedded PAN) belongs to a registered company; one with P belongs to a sole proprietor or individual.
How is the checksum calculated?▼
GSTN uses a base-36 modulus algorithm. Each of the first 14 characters is converted to a value (0-9 for digits, 10-35 for A-Z), multiplied by a factor (1 for odd positions, 2 for even), folded if the product exceeds 35, summed, and the checksum is the value that brings the sum to a multiple of 36. The result is rendered back as a digit or letter.
Does a passing checksum guarantee the GSTIN is real?▼
No — only the official GST portal can confirm that. The checksum verifies the GSTIN is structurally legitimate (which catches typos, transcription errors, and made-up numbers), but it doesn't tell you whether GSTN has actually issued that GSTIN to a real, currently-registered business. For high-trust use cases, always also check gst.gov.in.
Is this tool free? Do you store the GSTINs I check?▼
Free, no signup. The validator runs entirely in your browser — no GSTIN you paste here ever leaves your device. There's no server call. Open DevTools → Network tab to confirm.
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