Skip to content
SimpleERP
Start free trialTalk to us
SimpleERP
Sign inStart free trial

Tools

GSTIN validator: check a GST number and read its state and PAN

Written for businesses in India. Elsewhere, start from your country page or the global tools.

Paste a GSTIN from a purchase bill or a customer's letterhead. The validator checks the format and the check character, then shows the state and the PAN inside it.

Start free trialTalk to us

In short

This free GSTIN validator from SimpleERP checks that a GST number has the right 15-character format and check digit, and reads the state code and PAN from it. It runs the same GSTIN check SimpleERP applies when you save a customer or supplier.

Result
Format and check digit valid
State (digits 1 to 2)
Tamil Nadu (33)
PAN (characters 3 to 12)
AAACL1234A

This checks the format offline. It does not confirm the GSTIN is active on the GST portal.

Format and check digit valid

How to use it

Spaces and lower-case letters are fine; the validator trims and capitalises before it checks.

  1. Paste the GSTIN

    All 15 characters, such as 33AAACL1234A1ZG.

  2. Read the verdict

    Valid format, or the exact problem: wrong length, a letter where a digit belongs, or a check character that does not match.

  3. Check the state and PAN

    The first two digits name the state, and characters 3 to 12 are the PAN. Even a mistyped GSTIN shows a state guess, so you can see where it went wrong.

What is each character of a GSTIN?

It is 15 characters, not 16; a 16th character is always a typo. Each position has a job, as notified; check the current rules for special registrations such as TDS deductors and non-resident taxpayers, which follow a different pattern.

  • Characters 1 to 2: the GST state code, such as 33 for Tamil Nadu or 29 for Karnataka.
  • Characters 3 to 12: the holder's PAN.
  • Character 13: the registration number for that PAN in that state, 1 for the first, then 2 to 9 and A to Z.
  • Character 14: Z by default.
  • Character 15: a check character computed from the first 14, which catches most single typos.

Illustration of GST tax invoice INV-2026-27-0213 to Ravi Stores with CGST 9% and SGST 9%, round off, a UPI QR code and the amount in words.

Both GSTINs print on a tax invoice, the seller's and the buyer's.

Does a valid format mean the GSTIN is registered?

No. A valid format and check character mean the number could exist. Whether it is active, cancelled or suspended is only on the GST portal's Search Taxpayer page.

  • Use the validator to catch typos before you save a supplier or print an invoice.
  • Use the [GST portal](https://www.gst.gov.in/) to confirm a new supplier is active before you rely on input tax credit from them.
  • Match the PAN in the GSTIN against the PAN on the supplier's documents.

Do this automatically in SimpleERP

SimpleERP runs the same check every time a GSTIN is typed into a customer, supplier or your own business profile, and uses the state code to decide the tax on every invoice.

  • A wrong GSTIN is stopped at entry, with the reason shown under the field.
  • The state fills itself from the first two digits.
  • Place of supply for each invoice starts from the customer's state, so CGST and SGST or IGST is chosen for you.

Illustration of the keyboard-first invoice editor with a focused line, live tax totals and shortcut hints.

The invoice editor reads the customer's state from their GSTIN.

The maths

How it is calculated

The check character is a mod-36 checksum over the first 14 characters.

  1. Turn each character into a value: 0 to 9 stay as they are, A is 10, B is 11, up to Z at 35.
  2. Multiply the values in odd positions by 1 and in even positions by 2.
  3. For each product, add its quotient and remainder when divided by 36, and sum them all.
  4. The check value is (36 − sum mod 36) mod 36, turned back into a character.

Example

Worked example

Lakshmi Steel Furnitures, Coimbatore. Its GSTIN 33AAACL1234A1ZG reads like this.

CharactersValueMeaning
1 to 233Tamil Nadu
3 to 12AAACL1234APAN; the fourth letter C marks a company
131First registration for this PAN in Tamil Nadu
14ZDefault
15GCheck character: matches, so the format is valid
33AAACL1234A1ZG, character by character

Change the last character to 5 and the validator reports a check character mismatch, while still showing Tamil Nadu and PAN AAACL1234A.

Honest limits

What this validator does not do

  • It does not look the GSTIN up on the GST portal, so it cannot tell you the legal name or whether the registration is active.
  • Special GSTINs for TDS deductors, UN bodies and non-resident online service providers follow other patterns and may show as invalid.

FAQ

Questions, answered

Can a GSTIN be checked without the portal?

The format and the check character can, which catches most typos; this validator does that. Whether the GSTIN is active and whose it is can only be confirmed on the GST portal's Search Taxpayer page.

How do I find the state from a GST number?

Read the first two digits. They are the GST state code: 33 is Tamil Nadu, 29 is Karnataka, 27 is Maharashtra and 07 is Delhi.

Is the PAN part of the GSTIN?

Yes. Characters 3 to 12 of a regular GSTIN are the holder's PAN, so one business registered in two states has two GSTINs with the same PAN.

Why is the 14th character of a GSTIN always Z?

It is a default character in the current format, reserved for future use. A GSTIN with any other letter there fails the format check.

Related

Run your whole business from one simple place.

Seven days free. No card. Your first GST invoice in minutes.

Start free trialTalk to us