A GSTIN has 15 characters: the first two digits are the state code (27 for Maharashtra, 29 for Karnataka, 07 for Delhi, etc.), the next 10 characters are the PAN of the business, the 13th character is the entity number (Z for the first registration), the 14th is always Z, and the 15th is a check digit. Zoho Books validates the format of GSTIN entries and alerts you if the state code in the GSTIN does not match the state in the address, a common data quality issue.
Every B2B invoice in Zoho Books displays your GSTIN and the customer’s GSTIN on the invoice document. This is a mandatory GST compliance requirement. The state code embedded in both GSTINs is what Zoho Books uses to determine whether the supply is intra-state (both GSTINs have the same state code) or inter-state (different state codes), and therefore whether to apply CGST+SGST or IGST.
Zoho Books can verify a GSTIN against the GST portal database to confirm that the registration is active and that the trade name matches. This helps avoid the scenario where you raise an invoice with a customer’s incorrect or lapsed GSTIN, which would cause a mismatch in their GSTR-2A and prevent them from claiming ITC on your invoice. Use the GSTIN verification feature when adding new customers to prevent this issue upfront.
GSTIN is the 15-character unique GST registration number issued to every registered Indian business. Zoho Books uses it to identify transaction parties, determine supply type (intra/inter-state), and populate GST return data.
Enter your GSTIN in Settings, then Organisation Profile, Tax Information. Enter each customer’s and vendor’s GSTIN in their contact records. Zoho Books validates the format and uses GSTINs to auto-determine supply type for tax calculations.
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