How GST is calculated
To add GST: tax = base × rate ÷ 100. To remove it from an inclusive price: base = price ÷ (1 + rate ÷ 100). A ₹10,000 invoice at 18% becomes ₹11,800; an ₹11,800 inclusive bill contains ₹1,800 of GST. For sales within a state the tax splits equally into CGST and SGST; interstate sales charge IGST at the full rate.
GST slabs in 2026
Essentials such as food grains are nil or 5%, most goods and services are 12% or 18%, and luxury or sin goods like cars and tobacco attract 28% plus cess. Check the HSN or SAC code of your item for the exact rate.
Who needs to charge GST
Businesses with turnover above ₹40 lakh (₹20 lakh for services and in special-category states) must register. Registered buyers can claim input tax credit on GST paid on purchases, so the inclusive versus exclusive distinction matters for invoicing.
Frequently asked questions
What is the difference between CGST, SGST and IGST?
CGST goes to the centre and SGST to the state on intra-state sales, each at half the rate. IGST applies to interstate sales at the full rate.
How do I find the GST rate for my product?
Search the CBIC GST rate finder by HSN code for goods or SAC code for services.
Is GST charged on the MRP?
MRP already includes GST. Use the 'inclusive' option to see how much tax is inside a printed price.