Why the rate list looks messy on purpose
Most “GST calculator India” pages still freeze the 2017 poster: 0, 5, 12, 18, 28. That poster is how a lot of us learned the tax. It is not how a September 2025 invoice is supposed to look for a blender or a compact car. The 56th GST Council meeting cut the middle slabs for most goods. Everyday merit items clustered at 5%. The default became 18%. A 40% peak picked up many luxury and sin lines that used to wear 28% plus a compensation cess. Tobacco still has its own ugly corner of the schedule. If your CA sends a working paper with 12% on it, they might be looking at a credit note from FY 2024-25, or at a leftover HSN that did not move. This tool keeps 12% and 28% so you can reverse an old bill without lying that those are the current default.
Worked example: exclusive 18% intra-state
Taxable value ₹10,000. Rate 18%. GST = ₹1,800. Total = ₹11,800. Because the supply is intra-state, CGST ₹900 and SGST ₹900. IGST is zero. That is the textbook split in section 8 of the CGST Act read with the IGST Act: same-state supplies do not use IGST.
Worked example: inclusive 5% on an MRP
Sticker ₹210, tax included, 5%. Taxable value = 210 / 1.05 = ₹200. GST = ₹10. If you ship that pack to another state, the ₹10 is IGST, not a 5+5 split. People blow this on e-commerce: they apply CGST/SGST because the warehouse and the billing entity share a city, while the place of supply is the customer’s state.
Worked example: 40% peak on a notified luxury line
Exclusive ₹20,00,000 at 40% is ₹8,00,000 tax and ₹28,00,000 total. Do not treat 40% as “28 plus cess rounded up.” Cess had its own base and exemptions. If the notification puts the HSN at 40%, use 40%. If it still carries cess, this calculator will understate the outlay — that is an edge case, not a rounding bug.
Mistakes I see in Slack screenshots
Applying 18% to a 5% HSN because “everything is 18 now” is how you lose a notice. GST 2.0 did not delete exemptions: unbranded cereals, a lot of health-adjacent lines, and several public services stayed nil or merit. Reverse charge on specified services still exists; this page will not warn you. Rounding: Rule 56 talks about tax payable, but invoice software usually rounds per line. I show two decimals and stop. Composition dealers cannot use these rates as if they were a regular taxpayer. And “inclusive” is not a discount — it is algebra. If you type the GST-exclusive figure into inclusive mode you will understate tax by rate/(100+rate).
What this page refuses to do
It will not look up your HSN. CBIC’s goods and services rate finder is the source for “what rate sits on this item.” I keep the calculator stupid on purpose: you supply the rate, it does inclusive or exclusive arithmetic and shows CGST/SGST versus IGST. E-invoicing IRN generation, GSTR-1, and composition turnover tests live in GSTN, not here. If you are deciding whether a supply is goods or a restaurant service, that is a classification fight. This box will happily tax the wrong story at the right rate.
Worked algebra you can check with a pencil: exclusive tax = amount × rate/100. Inclusive taxable value = amount / (1 + rate/100). Intra-state splits the tax half and half. Inter-state puts the same rupees in IGST. If your invoice software disagrees by ₹0.01, it rounded a line before the total. I do not.
Questions
What GST rates should I use after GST 2.0?
Start with 5% and 18% for ordinary goods, 0% if the schedule says exempt, 40% only when the HSN is in the peak list. Confirm on the CBIC goods-and-services rates page, not a random carousel.
When do I split CGST and SGST versus IGST?
Intra-state: half and half. Inter-state: full IGST. Place of supply is a legal test (goods vs services have different sections), not “where I clicked calculate.”
Does this send my invoice values anywhere?
No. The amount field is never sent anywhere — the trust rail line should stay at “has not contacted any outside site” as you type. Ads on the page do not count toward that check.
How do I peel GST out of MRP?
Inclusive mode. Divide by 1 + rate/100.
Is 40% equal to old 28% plus cess?
Only if the notification says so for that HSN. Many cessed items moved; some did not in the way Twitter claimed.
Can I file GSTR-1 from this?
No. It is a line check.
Why keep 12% and 28%?
Credit notes, unamended contracts, and tobacco-adjacent schedules. Switch the era to “Before 22 Sep 2025” when the invoice date is actually that old; on GST 2.0 they stay labeled as legacy so you do not pick them on a 2026 retail invoice by muscle memory.
Can I save this GST split?
Save JSON worksheet or print the worksheet. That file stays on your computer. Remember on this device keeps the last rate in this browser only — not an account, not uploaded.