Last updated: 23 October 2026
Type an amount, choose whether it is before GST or already includes GST, pick the rate and the buyer's state. The answer updates as you type, with each step of the working written out. Amounts are rounded to the paisa.
How do you add GST to a price?
Multiply the price by the rate and divide by 100. That is the GST. Add it to the price to get the bill total.
- GST = price × rate ÷ 100
- Total = price + GST
Example: goods worth ₹10,000 at 18%. GST = ₹10,000 × 18 ÷ 100 = ₹1,800, and the total is ₹11,800. If the buyer is in your state, show it as CGST 9% (₹900) and SGST 9% (₹900).
How do you take GST out of an amount that includes it?
When a price already includes GST, for example a customer's budget or an MRP, divide it by (100 + rate) and multiply by 100. That gives the price before GST. The difference is the GST.
- Price before GST = amount × 100 ÷ (100 + rate)
- GST = amount − price before GST
Example: ₹11,800 including 18%. Price before GST = ₹11,800 × 100 ÷ 118 = ₹10,000, and GST = ₹1,800. A common mistake is to take 18% of ₹11,800, which gives ₹2,124. That is wrong, because the 18% was charged on ₹10,000, not on ₹11,800. For a medicine strip with an MRP of ₹105 at 5%, the price before GST is ₹100 and the GST is ₹5.
CGST + SGST or IGST: which one goes on the bill?
It depends on where the supply is made, called the place of supply. For goods delivered to a buyer, compare the buyer's state with yours:
- Same state: charge CGST and SGST, each at half the rate. At 5%, that is CGST 2.5% + SGST 2.5%. In a Union Territory without its own legislature, UTGST takes the place of SGST.
- Another state: charge the full rate as IGST. At 5%, that is IGST 5%.
The total tax is the same either way; only the split changes. The first two digits of a GSTIN are the state code, so the buyer's GSTIN tells you the state: 07 is Delhi, 09 Uttar Pradesh, 10 Bihar and 20 Jharkhand, for example.
What are the GST rates after 22 September 2025?
On the GST Council's recommendation at its 56th meeting, GST rates changed from 22 September 2025. The old four-slab structure of 5%, 12%, 18% and 28% became two main rates, 5% and 18%, plus a special rate of 40% for a few goods. The rate notification for goods, Notification 9/2025-Central Tax (Rate), has these schedules (the total GST is shown; CGST and SGST are half each):
| GST rate | What it covers (examples) |
|---|---|
| Nil | Exempt and nil-rated goods, such as the 33 life-saving drugs moved from 12% to nil, UHT milk, pre-packaged paneer and Indian breads |
| 0.25%, 1.5% and 3% | Special low rates for a small group of goods, mainly precious metals, jewellery and precious stones (Schedules V, VI and IV) |
| 5% | Merit rate: drugs and medicines (except those at nil), medical devices, many packaged foods such as namkeen, butter and ghee, bicycles, agricultural machinery |
| 18% | Standard rate: most other goods, for example TVs, air conditioners, small cars, motorcycles up to 350 cc, cement and auto parts |
| 40% | Special rate for a few goods: mid-size and big cars, motorcycles above 350 cc, other non-alcoholic beverages and, from 1 February 2026, pan masala, cigarettes and most tobacco products |
Pan masala, cigarettes, chewing tobacco and some other tobacco products stayed at 28% plus compensation cess until 31 January 2026; from 1 February 2026 they moved to 40% (bidis to 18%), and the 28% schedule was removed.
What this calculator does not do
- It doesn't look up the rate for your item. Find the rate for your HSN code first.
- It doesn't add compensation cess, TCS or TDS.
- It rounds to the paisa. Your bill may round each line, or the bill total, to the rupee, so totals can differ by a few paise.
Let your billing software do it on every bill
Working out GST by hand is fine for one amount, not for a hundred bills a day. ValueSoft applies CGST and SGST or IGST from the party's state on every bill, keeps input and output GST in separate ledgers, and gives you GSTR-1 and GSTR-3B from your own bills. It files them from the software or exports GSTR-1 as Excel, CSV or JSON, matches purchases with GSTR-2A and GSTR-2B, and makes e-Invoices and E-Way Bills from the bill. These GST features come in the Mini, Lite, Plus and Max plans; see pricing.
GST worked out on every bill
Download the free demo or book a demo with our team. We'll show GST billing, GSTR-1 and GSTR-2B matching on your kind of bills.
Sources
- GST Council / PIB: recommendations of the 56th GST Council meeting (3 September 2025)
- GST Council / PIB: FAQs on the decisions of the 56th GST Council meeting (dates, medicines at 5%, cars, section 14 for supplies around the change)
- Government of West Bengal, GST Policy Planning Unit: rate schedules under Notification 9/2025-Central Tax (Rate)
- GST Council newsletter, December 2025 (Notification 19/2025-Central Tax (Rate): tobacco products at 40% and bidis at 18% from 1 February 2026; Schedule VII (28%) omitted; compensation cess withdrawn)
