When is GST registration mandatory for a startup?

Registration is mandatory once aggregate turnover crosses the threshold — broadly ₹40 lakh for goods and ₹20 lakh for services (lower in some special-category states). But several triggers require registration regardless of turnover: inter-state taxable supplies, selling through e-commerce operators, and cases where tax is payable under reverse charge.

Exporters — including Indian subsidiaries billing their foreign parent — generally register even though exports are zero-rated, because registration (with an LUT) is what lets you export without charging IGST and claim input refunds.

Voluntary early registration can make sense for B2B startups whose customers want input credit. The right answer depends on your supply chain — worth thirty minutes of advice before your first invoice.