Validate any GSTIN number format, calculate CGST/SGST/IGST split, and verify your invoice meets GST compliance rules. Free GST calculator for Indian businesses.
GSTIN (Goods and Services Tax Identification Number) is a 15-character code. Format: 2-digit state code + 10-character PAN + 1 entity number + Z + 1 check digit. You can validate format with this tool, but network verification requires the GST portal.
For intrastate transactions (buyer and seller in same state): CGST (Central GST) + SGST (State GST), each at half the total GST rate. For interstate transactions: IGST (Integrated GST) at the full rate. Example: 18% GST intrastate = 9% CGST + 9% SGST.
Most professional services (consulting, IT, advertising) attract 18% GST. Educational services, healthcare, and some financial services are exempt (0%). Hotels above ₹7,500/night: 18%. Hotels under ₹1,000/night: 0%.
Under RCM, the buyer (recipient) pays GST instead of the supplier. It applies to: purchases from unregistered dealers (in some categories), import of services, and specific notified supplies. The buyer can claim input tax credit on RCM payments.
Businesses with annual turnover above ₹20 lakh (₹10 lakh in special category states) must register for GST. For e-commerce sellers and interstate suppliers, registration is mandatory regardless of turnover. Voluntary registration is also allowed.
ITC allows businesses to deduct GST paid on purchases from GST owed on sales. If you pay ₹18,000 GST on inputs and collect ₹30,000 on sales, you only pay ₹12,000 net. ITC cannot be claimed on personal expenses or blocked credits.
GSTR-1 (outward supplies): 11th of following month (monthly) or quarterly. GSTR-3B (summary return + payment): 20th of following month. Annual return GSTR-9: 31st December of the following financial year. Late filing attracts ₹50-200/day penalty.