GSTIN Validator – India

A Goods and Services Tax Identification Number (GSTIN) is a unique 15-character alphanumeric identifier assigned to every taxpayer registered under GST in India. It is required on all GST invoices and tax filings.

GSTIN Structure

• Characters 1–2: Two-digit state code (01–37, 97, 99) identifying the registered state
• Characters 3–12: The holder's 10-character PAN number
• Character 13: Entity number (1–9, A–Z) — allows multiple registrations per PAN within a state
• Character 14: Always "Z" (default character)
• Character 15: Checksum character computed using a weighted sum algorithm

Checksum Algorithm

Each character is assigned a position weight (alternating 1 and 2). The character's numeric value (0–9 = 0–9, A–Z = 10–35) is multiplied by its weight. Products are split into tens and units, both are summed, and the checksum character makes the total a multiple of 36.

Important Note

This tool validates the format and checksum of a GSTIN. It does not verify active registration status with the GST portal. For official verification, use the GST Portal (gst.gov.in).