GST Calculator (2026 Rates)
Add GST to a price or pull it back out of a total, at any of the current rates. The calculator shows the CGST and SGST split for a supply inside your state, or IGST when you are billing another state.
Updated for GST 2.0 rates effective 22 September 2025
Intra-state supply — the tax splits equally into CGST and SGST.
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How GST is calculated
GST is a destination-based tax charged on the taxable value of a supply. The calculation itself is simple — the taxable value multiplied by the applicable rate — but two things decide what you actually put on the invoice: which rate applies to what you are selling, and where your customer is located.
When the price you have agreed already includes tax, you need to work backwards. This is common in retail, where a shelf price is quoted to the customer as a single figure. Dividing by one plus the rate gives you the taxable value, and the difference is the GST you must report.
Intra-state versus inter-state supply
If your place of business and the place of supply are in the same state, the tax is collected half by the Centre and half by the state, shown on the invoice as CGST and SGST. If they are in different states, the whole amount is collected as IGST. Getting this wrong is one of the most common reasons a customer's input tax credit gets held up, so it is worth checking the state code on their GSTIN before you raise the invoice.
What changed under GST 2.0
The 56th GST Council meeting simplified a five-slab structure into four working bands. The practical effect for most small businesses is that the 12% and 28% slabs no longer exist. If you are working from an older rate chart, or from software that has not been updated, you may still be charging a rate that was withdrawn — worth a quick audit of your item master.
Frequently asked questions
- What are the GST rates in India right now?
- Since the GST 2.0 reform of 22 September 2025 there are four main rates: 0%, 5%, 18% and 40%. The old 12% and 28% slabs were withdrawn — most 12% items moved to 5% or 18%, and most 28% items moved to 18%. A 40% band now covers luxury and sin goods such as tobacco and pan masala. Separately, gold, silver and finished jewellery are taxed at 3%, and rough diamonds at 0.25%.
- How do I remove GST from a total that already includes it?
- Divide the total by (1 + rate/100). For an 18% rate, ₹11,800 ÷ 1.18 gives a taxable value of ₹10,000, so the GST included is ₹1,800. Choose the 'GST included' option above and the calculator does this for you.
- When do I charge CGST and SGST instead of IGST?
- It depends on the place of supply. If your business and your customer are in the same state, the tax splits equally into CGST and SGST — 18% becomes 9% plus 9%. If the customer is in another state, or the supply is an export or to an SEZ, you charge the whole amount as IGST. The total tax is identical either way; only the split changes.
- Is GST calculated before or after a discount?
- GST is charged on the value after any discount shown on the face of the invoice. Discounts agreed before or at the time of supply reduce the taxable value. Post-sale discounts only reduce it if they were agreed in advance and can be linked to specific invoices.
- Do I need to show the HSN code on my invoice?
- Yes, in most cases. If your aggregate annual turnover is up to ₹5 crore, a 4-digit HSN code is mandatory on B2B invoices. Above ₹5 crore, a 6-digit HSN code is required on all invoices.
Related free tools
- GST Invoice Generator
Create a GST-compliant tax invoice and download it as a PDF in under a minute. No sign-up, no watermark.
- HSN & SAC Code Finder
Search HSN and SAC codes by product or service name and get the applicable 2026 GST rate.
- GSTIN Validator
Check whether a GSTIN is structurally valid, and decode the state, PAN and entity details it contains.
Charging GST on real invoices?
Doing the maths is the easy part. Smart Dhandha keeps the rest of it straight — client records, invoice numbering that never repeats, the CGST/SGST/IGST split picked automatically from the place of supply, and a running view of who still owes you money.
- GST-ready invoices with the tax split handled for you
- Automatic invoice numbering and payment tracking
- Books, payroll and compliance in the same place
This tool is provided free for general guidance and uses the rates noted above. Statutory rates change, and individual circumstances differ — please confirm with your accountant or a qualified professional before relying on these figures for filing or payroll.