GSTIN Validator

Validate and decode GSTIN with state and entity details

Finance & BusinessFREEYour data never leaves your browser

100% freeNo signupRuns in your browser

Built by WOWHOW Team · 14+ yrs engineering

GSTIN Validator is a free, browser-based tool that lets you validate and decode gstin with state and entity details — with zero signup, zero installation. Your data never leaves your browser. Part of 138+ free developer and business tools at wowhow.cloud, built and maintained by a team with 14+ years of hands-on development experience.

TOOLGSTIN Validator

GSTIN (15 characters)

0/15

Character Breakdown

—

State Code

—

PAN

—

Entity No.

—

Default

—

Check Digit

About GSTIN Validator

GSTIN errors on purchase invoices invalidate Input Tax Credit claims — even a single transposed character in a 15-digit number can cause GSTR-2B mismatches and ITC rejection. Before adding a new vendor or accepting a supplier invoice, validating the GSTIN's structure and check digit is a critical first step. This tool runs the full offline validation instantly, decodes the embedded state code, PAN, and entity type, and supports bulk validation for accounts payable teams.

How It Works

A GSTIN follows a strict 15-character format under the GST Registration Rules: characters 1-2 encode the state code (01 = Jammu & Kashmir through 38 = Ladakh), characters 3-12 are the registrant's PAN, character 13 is the entity number (1-9 or A-Z), character 14 is a fixed 'Z', and character 15 is an alphanumeric check digit.

The check digit validation uses the GST Council's published mod-36 algorithm: each character is mapped to a numeric value (0-9 for digits, 10-35 for A-Z), a weighted alternating sum is computed, and the remainder modulo 36 is converted back to the check digit character. If the computed check digit does not match position 15, the GSTIN is structurally invalid.

The entity type is decoded from the 4th character of the embedded PAN (position 6 of the GSTIN): P = Individual, C = Company, H = HUF, F = Firm, A = AOP, T = Trust, B = BOI, G = Government, L = Local Authority.

Who Is This For

An accounts payable executive validating 150 new vendor GSTINs from a procurement batch before adding them to the ERP system.

A freelancer checking a client's GSTIN before raising an invoice, to ensure the correct state code appears and inter-state IGST applies.

A GST practitioner catching check digit errors in a client's data before filing GSTR-1 to avoid ITC mismatch notices.

A finance team lead building a quick validation step into their invoice approval workflow using the bulk mode.

Scope note: Validates GSTIN format and check digit using the GSTN offline algorithm. Does not make live API calls to the GSTN server — a structurally valid GSTIN may still be inactive, suspended, or cancelled on the live portal. For compliance-critical transactions, always verify live registration status at the official GST portal. UIN (Unique Identity Number) for embassies uses a different 15-character format not covered here.

Disclaimer: This calculator is for informational and educational purposes only and does not constitute financial, tax, or legal advice. Results are estimates based on publicly available tax slabs and formulas. Consult a qualified Chartered Accountant, tax professional, or financial advisor for guidance specific to your situation. Built and maintained by the WOWHOW Team with 14+ years of software development experience.

How to Use

Type or paste a 15-character GSTIN in the input field

See real-time validation with character-by-character breakdown

View the decoded state, PAN, entity type, and check digit status

Switch to Bulk mode to validate multiple GSTINs at once

Frequently Asked Questions

GSTIN is 15 characters: first 2 = state code (01-37), next 10 = PAN of the registered entity, 13th = entity number (1-9, A-Z), 14th = Z (default), 15th = check digit (alphanumeric).

The check digit uses a mod-36 algorithm on the first 14 characters. Each character is mapped to a numeric value (0-9 for digits, 10-35 for A-Z), then processed using a weighted sum.

The 4th character of the embedded PAN indicates entity type: P = Individual, C = Company, H = HUF, F = Firm/Partnership, A = AOP, T = Trust, B = BOI, L = Local Authority, G = Government.

Yes. This tool validates the structural format and check digit offline. For live registration status, use the "Check on GST Portal" button to search on the official GSTN portal.

The tool validates the 15-character structure and the check digit — both of which are checkable offline. However, a GSTIN could be structurally valid but cancelled, suspended, or never registered on the GSTN server. Always cross-check live status on the GST portal before accepting a GSTIN from a new vendor.

The 13th character is the entity number (also called the registration count), ranging from 1-9 and A-Z. It indicates how many registrations the same PAN holder has in that state — 1 being the first, 2 the second, and so on. Large businesses with multiple branches in one state have different GSTINs with different 13th characters.

Yes. Switch to Bulk mode and paste your list of GSTINs (one per line or comma-separated). The tool runs the format and check digit validation on each entry and flags invalid ones, making it efficient for accounts payable teams to clean up vendor master data.