VAT/GST Registration Number: What to Enter in the Form

Billing forms from Google, Meta, Apple, Microsoft, AWS, airlines and hotel sites often ask for a VAT/GST registration number, usually followed by "if applicable". For a business in India, the answer is short: it is your GSTIN, and if you do not have one, you leave the field empty. What is less obvious is that entering it changes who pays the tax and whether you can claim it back. This guide explains both.

What "VAT/GST registration number" means in India

Global software forms are built once for every country. In the UK or the EU the field wants a VAT number; in Australia, Singapore or Canada, a GST number. The label covers both. India's indirect tax changed from state VAT, central excise and service tax to GST on 1 July 2017, and every registered business was issued a GSTIN: a 15-character identifier made of the state code, the PAN, an entity number, the letter Z and a check character. The GSTIN format guide breaks it down character by character.

Where you will see the field

• Advertising accounts — Google Ads, Meta, LinkedIn and similar billing settings.
• Cloud and SaaS subscriptions — hosting, design tools, developer platforms.
• App store developer accounts.
• Travel — airline and hotel bookings, where the GST details decide whether the invoice is issued to the business.
• E-commerce checkout, where it is usually labelled "GSTIN (optional)" — covered in GSTIN optional meaning.

Enter it, or leave it blank?

Foreign vendors: what entering a GSTIN changes

When a supplier outside India sells online services into India, GST applies in one of two ways:

• To a non-business recipient — an individual, or a business that gives no GSTIN — the foreign supplier is responsible for the tax as an OIDAR supplier. It charges IGST on the bill and pays it to the Indian government.
• To a registered business — the supply is an import of services, and the Indian business pays IGST itself under reverse charge, then claims it as input tax credit if the purchase qualifies.

The GSTIN you enter is how the supplier tells the two apart. With it, the invoice shows no Indian GST, and the reverse charge entry goes into your GSTR-3B. Without it, you pay the supplier's GST and, having no proper invoice to your GSTIN, usually cannot claim it. The full rules are in our guides to OIDAR services and reverse charge.

Indian vendors: the B2B invoice

When the supplier is in India, your GSTIN turns a consumer invoice into a B2B tax invoice. The supplier reports it in GSTR-1 against your GSTIN, it appears in your GSTR-2B, and you can claim the credit subject to the usual conditions in the ITC rules. Without the GSTIN, the sale is reported as B2C and no credit reaches you, however valid the purchase.

Mistakes that cost the credit

• A GSTIN from the wrong state. A business registered in Maharashtra and Karnataka should use the GSTIN of the state in the billing address. The place of supply follows the address.
• A legal name that does not match. Use the legal name as registered, not a brand name. See legal name vs trade name.
• A cancelled or suspended GSTIN. The supplier's system may accept any correctly formatted number, but credit depends on your registration being active.
• A typo. One wrong character sends the invoice to another business's GSTR-2B, or to nobody's. Paste from the certificate, and check the result.

Old VAT TIN numbers

Before GST, each state issued an 11-digit VAT TIN. Those numbers stopped being used when GST began, and existing dealers were migrated to GSTINs. A form asking for a VAT number today wants the GSTIN. If you are reconciling old records, the old TIN has no role in any current return.

Frequently asked questions