Indian GSTIN Structure and Checksum Guide

An Indian GSTIN is a 15-character identifier. Test fixtures commonly represent a state code, PAN-shaped taxpayer portion, entity sequence, Z placeholder and final base-36 checksum character.

Generate fixture values

The GST Number Generator lets you choose a state code and entity type, then creates a synthetic GSTIN with a calculated final check character. Generated values are designed for invoice integration tests; they are not registrations.

Validate the checksum

Check the 15-character pattern first, then calculate the checksum over the first 14 characters with the 0–9 and A–Z alphabet. Keeping format and checksum failures separate makes automated test failures easier to diagnose.

Use in invoice tests

Retain state, entity and checksum metadata with the value when exporting fixtures. Real GST records must be verified through the appropriate official process before production use.