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GST Number Validator

100% Free

Validate an Indian GSTIN's format and checksum instantly, then extract its state code, PAN, and taxpayer type — all in your browser, nothing uploaded.

Checksum Verified
Instant
100% Client-Side
No Sign Up

1. Enter GSTIN to validate

Example: 27AAPFU0939F1ZV. Validation runs instantly in your browser.

15 characters long
Valid GSTIN structure
Recognised state code
Checksum digit matches

This checks GSTIN format and checksum only. It cannot confirm a GSTIN is actively registered with the GST portal.

2. Validation result

Valid GSTIN
The format and checksum are correct.
GSTIN
27AAPFU0939F1ZV
State Code
27
State / UT
Maharashtra
PAN
AAPFU0939F
Taxpayer Type
Firm / LLP
Entity Number
1
Checksum
V

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Add GST Number Validator to your website or blog in seconds.

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<iframe
  src="https://tools.town/embed/gst-number-validator/"
  width="100%"
  height="600"
  style="border:none; border-radius:12px;"
  loading="lazy"
  title="GST Number Validator">
</iframe>

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How to Use

  1. 1 Type or paste a 15-character GSTIN
  2. 2 The tool normalises spaces and lower-case automatically
  3. 3 Watch each check pass: length, structure, state code, checksum
  4. 4 Read the extracted state, PAN, and taxpayer type
  5. 5 Fix any flagged issue and re-check instantly

Features

  • Full 15-character GSTIN structure validation
  • Mod-36 checksum digit verification
  • Extracts state code and state/UT name
  • Pulls out the embedded PAN and taxpayer type
  • Clear pass/fail checklist with the exact failing reason
  • Runs entirely in your browser — nothing is uploaded

Why it Matters

An invalid GSTIN on an invoice can hold up input-tax-credit claims and trigger compliance headaches. A quick format and checksum check catches typos before they reach your books or your filing. It won't replace a portal lookup, but it instantly rules out numbers that can't possibly be genuine.

★★★★★

Use Cases

Invoice Checks

Catch mistyped supplier GSTINs before recording an invoice

Data Cleanup

Spot malformed GST numbers when cleaning a vendor list

Onboarding

Sanity-check a new client or vendor's GSTIN format

Self-Verification

Confirm your own GSTIN's parts decode correctly

What this tool does

The GST Number Validator checks whether an Indian GSTIN is well-formed and passes its checksum, then breaks it into its parts: state code, state name, embedded PAN, taxpayer type, entity number, and check digit.

How it works

It runs three checks — the 15-character structure, a recognised state code, and the official mod-36 checksum over the first 14 characters — then decodes the parts. The logic is a pure function and runs fully offline.

Informational only

This is a format and checksum validator, not a registration lookup. It cannot confirm a GSTIN is active or correctly registered. For any legal or financial decision, verify the number on the official GST portal.

Privacy

Everything runs locally in your browser. No values are uploaded, logged, or stored.

Frequently Asked Questions

What makes a GSTIN valid?
A GSTIN is 15 characters: a 2-digit state code, a 10-character PAN, a 1-character entity number, the letter 'Z' by default, and a final checksum character. The checksum is computed with a base-36 (mod 36) algorithm over the first 14 characters. This tool checks the structure, the state code, and the checksum.
Can this tool confirm a GSTIN is actually registered?
No. It validates format and checksum only — it works fully offline and never contacts the GST portal. A number can be structurally valid yet not issued to anyone, so for legal confirmation always verify on the official GST portal.
How do you extract the PAN from a GSTIN?
Characters 3 to 12 of a GSTIN are the holder's 10-character PAN. The fourth character of that PAN indicates the taxpayer type — for example 'P' for individual, 'C' for company, or 'F' for firm/LLP — which the tool decodes for you.
What does the state code mean?
The first two digits identify the state or union territory of registration, following the official GST state-code list (for example 27 is Maharashtra, 07 is Delhi, 29 is Karnataka). The tool maps the code to its state name automatically.
Is my GST number stored anywhere?
No. Validation runs entirely in your browser. Nothing you type is uploaded, logged, or stored — refreshing the page clears everything.
📖

Want to understand the math?

Browse all guides →
How GSTIN Works
gstin

How GSTIN Works: Structure, State Codes and Checksum

A plain-English breakdown of the 15-character Indian GSTIN — what each part means, how the checksum is computed, and how to spot an invalid number before it costs you.

23 Jun 2026

5 min read

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