How do I remove GST from a price that includes it?

Divide by 100 plus the rate and multiply by 100 to get the taxable value. ₹11,800 including 18% GST is ₹11,800 × 100 ÷ 118 = ₹10,000, and the GST is ₹1,800.

When do I charge CGST and SGST, and when IGST?

CGST and SGST when the supplier and the place of supply are in the same state, IGST when they are in different states. In a union territory such as Chandigarh or Ladakh, UTGST takes the place of SGST.

What are the GST rates now?

Since 22 September 2025, goods carry 5%, 18% or, for a few, 40%. Gold, silver and jewellery carry 3%, and diamonds and precious stones 0.25% or 1.5%. Some goods notified separately, such as bricks and roofing tiles, carry 12%. Pan masala and tobacco moved from 28% to 40% on 1 February 2026.

Is there still a 28% GST rate?

Not in the goods rate schedules. Their 28% schedule kept pan masala and tobacco after 22 September 2025, and was omitted from 1 February 2026 by Notification 19/2025-Central Tax (Rate).

Should GST on an invoice be rounded to the rupee?

The CGST Act rounds tax payable to the rupee in returns and payments. It doesn’t say how to round an invoice, so most show tax to the paisa and many round the invoice total on a “round off” line.

Is what I type saved or sent anywhere?

No. The figures are worked out in your browser. Nothing is sent, stored or tracked by the calculator.

Can PrimoERP work out GST on my invoices?

Yes. PrimoERP puts GST on every invoice and bill, with the place of supply set from both GSTINs, so CGST and SGST or IGST is chosen for you.

GST Calculator: Add or Remove GST, CGST, SGST

GST calculator

Work out GST on

The amounts are

Supplier’s state

Place of supply

Usually where the goods are delivered or the buyer is.

Same state: CGST and SGST, half the rate each.

Line 1
Description (optional)
Amount before GST (₹)
GST rate
Cess (%)
Line 2
Description (optional)
Amount before GST (₹)
GST rate
Cess (%)

The rate for your HSN or SAC code, from the rate notifications. Only a cess charged as a % of value. Leave blank if none.

Your GST

₹43,785.00GST ₹4,035.00 on a taxable value of ₹39,750.00.

Line	Taxable	Rate	CGST	SGST	Total
1. Steel utensils, HSN 7323	24,000	5%	600	600	25,200
2. Mixer grinders, HSN 8509	15,750	18%	1,417.50	1,417.50	18,585

How it’s worked out

GST = taxable value × rate ÷ 100
Total = taxable value + GST
CGST = SGST = taxable value × (rate ÷ 2) ÷ 100

Taxable value: ₹39,750.00
CGST: ₹2,017.50
SGST: ₹2,017.50
Total GST: ₹4,035.00
Total with GST: ₹43,785.00

In words: Rupees Forty-Three Thousand Seven Hundred Eighty-Five Only

Each tax is rounded to the paisa on each line. An estimate, not tax advice: check the rate for your goods with your CA. Nothing you type leaves this page.

How it’s worked out.

The rules the calculator applies, from the GST Acts and the rate notifications on CBIC’s tax information portal.

From 22 September 2025, IGST on goods is 5%, 18% or 40%, with 3% for gold, silver, pearls and jewellery, 0.25% for rough diamonds and precious stones, and 1.5% for other diamonds. A seventh schedule kept pan masala and tobacco at 28%.
Source: Notification 9/2025-Integrated Tax (Rate), checked 17 Oct 2026
Within a state or union territory, central tax is half that rate: 2.5% against 5%, 9% against 18%, 20% against 40%.
Source: Notification 9/2025-Central Tax (Rate), checked 17 Oct 2026
From 1 February 2026 that 28% schedule (14% central tax) was omitted: pan masala, cigarettes and most tobacco moved to 40%, and biris to 18%.
Source: Notification 19/2025-Central Tax (Rate), checked 17 Oct 2026
12% remains for some goods notified separately: fly ash bricks and blocks, building bricks and earthen or roofing tiles carry central tax at 6% from 22 September 2025.
Source: Notification 14/2025-Central Tax (Rate), checked 17 Oct 2026
Central tax is charged on the value of the supply under section 15, at the notified rate. So GST = taxable value × rate ÷ 100.
Source: CGST Act 2017, s.9(1), checked 17 Oct 2026
A supplier and a place of supply in two different states, two union territories, or a state and a union territory make an inter-state supply. It carries IGST.
Source: IGST Act 2017, s.5(1) and 7, checked 17 Oct 2026
A supplier and a place of supply in the same state or union territory make an intra-state supply. It carries CGST and SGST.
Source: IGST Act 2017, s.8, checked 17 Oct 2026
In a union territory, union territory tax (UTGST) is levied on intra-state supplies, alongside CGST.
Source: UTGST Act 2017, s.7, checked 17 Oct 2026
Union territory tax is notified at the same rates as central tax: 2.5%, 9%, 20%, 1.5%, 0.125% and 0.75%.
Source: Notification 9/2025-Union Territory Tax (Rate), checked 17 Oct 2026
A cess charged with reference to value is worked out on the same value as GST.
Source: GST (Compensation to States) Act 2017, s.8(2), checked 17 Oct 2026
Tax, interest, penalties and refunds under the Act are rounded to the nearest rupee: 50 paise or more goes up, less is dropped.
Source: CGST Act 2017, s.170, checked 17 Oct 2026

Where the rules are silent

Rounding on each line or on the total. The Acts don’t say whether an invoice rounds tax line by line or on the bill total. The calculator rounds each tax on each line to the paisa, then adds the lines. Rounding on the total can differ by a paisa or two.
Odd paise between CGST and SGST. CGST and SGST are each worked out at half the rate and rounded on their own, so they are always equal. Together they can be a paisa away from GST at the full rate: 18% of ₹10.25 is ₹1.85 as IGST, but ₹0.92 + ₹0.92 within a state.
Taking GST out of a price. Taxable value = price × 100 ÷ (100 + rate). Rounded to the paisa, its taxes don’t always add back to the price. The calculator moves the taxable value by up to 3 paise to find one whose taxes do. When none does, it keeps the nearest and shows the difference.
Rupee rounding on invoices. Section 170 rounds the tax you pay, in returns and payments, to the rupee. It doesn’t say how to round an invoice, so the calculator shows paise. Many invoices round the total to the rupee on a “round off” line.
SGST rates. Each state notifies SGST under its own GST Act. The calculator charges SGST at the same rate as CGST, half the GST rate. We read the central and union territory notifications, not each state’s.

One bill, line by line.

A wholesaler in Ahmedabad bills a shop in Surat, both in Gujarat: steel utensils for ₹24,000 at 5% and mixer grinders for ₹15,750 at 18%, before GST.

Steel utensils, HSN 7323at 5%: 24,000
CGST and SGST on the utensils600 + 600: 1,200
Mixer grinders, HSN 8509at 18%: 15,750
CGST and SGST on the grinders1,417.50 × 2: 2,835
Taxable value: 39,750
CGST600 + 1,417.50: 2,017.50
SGST: 2,017.50
Bill total, ₹: 43,785

₹39,750 + ₹4,035 GST = ₹43,785. Billed to a shop in Maharashtra instead, the same ₹4,035 would all be IGST.

An illustration, not tax advice. Steel utensils (7323) are in Schedule I and electro-mechanical domestic appliances (8509) in Schedule II of Notification 9/2025-Central Tax (Rate). Check the classification of your own goods.

What it does not cover.

Check these with your CA before you put the figures on an invoice.

Which rate your goods or service carry
The calculator doesn’t look up a rate from an HSN or SAC code. You pick the rate.
Goods rates are set out by Chapter, heading or tariff item in the seven schedules of Notification 9/2025-Central Tax (Rate).
Source: Notification 9/2025-Central Tax (Rate), checked 17 Oct 2026
Exempt goods
Pick 0% for them. The calculator doesn’t check whether your goods are exempt.
Goods in the schedule of Notification 10/2025-Central Tax (Rate) are exempt from central tax on intra-state supplies.
Source: Notification 10/2025-Central Tax (Rate), checked 17 Oct 2026
Place of supply
The calculator uses the place of supply you pick. It doesn’t work it out from the delivery address or the type of service.
When goods move, their place of supply is where the movement ends for delivery to the recipient.
Source: IGST Act 2017, s.10(1)(a), checked 17 Oct 2026
Reverse charge
When the buyer pays the tax, the supplier doesn’t collect it. The calculator doesn’t mark a bill as reverse charge.
The Government can notify supplies on which the recipient pays the tax, on reverse charge.
Source: CGST Act 2017, s.9(3) and 9(4), checked 17 Oct 2026
Composition dealers
A dealer in the composition scheme pays tax on turnover and can’t charge GST on its bills.
A taxable person in the composition scheme shall not collect any tax from the recipient on supplies made by him.
Source: CGST Act 2017, s.10(4), checked 17 Oct 2026
Exports and SEZ supplies
They are zero-rated, and a supply to an SEZ is inter-state even within one state. The calculator treats every bill as a supply within India.
Exports and supplies to an SEZ developer or unit for authorised operations are zero-rated supplies.
Source: IGST Act 2017, s.7(5) and 16(1), checked 17 Oct 2026
Cess other than a % of value
Only a cess charged as a percentage of value, not one per unit or per quantity. Compensation cess is now nil on pan masala, tobacco and a long list of other goods.
Compensation cess on pan masala and tobacco products was set to nil from 1 February 2026, after Notification 2/2025 did the same for other goods from 22 September 2025.
Source: Notification 3/2025-Compensation Cess (Rate), checked 17 Oct 2026
Discounts and what goes into the value
Enter the taxable value after any discount shown on the invoice. Section 15 decides what else belongs in it, such as packing or freight charged to the buyer.
A discount given before or at the time of supply, and recorded in the invoice, is not part of the value of the supply.
Source: CGST Act 2017, s.15(3)(a), checked 17 Oct 2026
TDS and TCS under GST
Tax deducted by a government buyer, or collected by an e-commerce operator, comes off the payment, not the invoice. It isn’t shown.
Government departments and notified persons deduct 1% from payments to a supplier where a contract’s taxable value exceeds ₹2.5 lakh.
Source: CGST Act 2017, s.51(1), checked 17 Oct 2026

More GST and compliance tools.

Work out GST, check a GSTIN, see whether e-invoicing or an e-way bill applies, and keep the due dates. And the tools that go with this one.

GSTIN validatorCheck the format and check digit of one GSTIN or a whole list, in your browser.Read more E-invoice applicability checkerWhether your business must issue e-invoices, and the 30-day reporting limit.Read more E-way bill checkerWhether a consignment needs an e-way bill, and how long the bill stays valid.Read more GST late fee and interest calculatorLate fee and interest on a late GSTR-3B, GSTR-1 or GSTR-9, day by day.Read more Compliance calendarGST, TDS, PF and ESI due dates, month by month, to add to your calendar.Read more GST invoice generatorA GST tax invoice with every required field, as a PDF or an Excel template.Read more Margin, markup and break-even calculatorMargin and markup from cost and price, with or without GST, and your break-even point.Read more Quotation generatorA quotation with GST, validity and terms, as a PDF or an Excel template.Read more All free toolsGST, invoices, payroll, inventory and accounting tools, free and with no signup.Read more

GST on every invoice, without a calculator.

PrimoERP works out each invoice’s GST from both GSTINs, and adds it up for your return.

GST accounting softwareEvery invoice and bill carries its GST, split into CGST and SGST or IGST, so your return figures come from your books.Read more Sales and invoicingQuote to order to invoice, with tax invoices numbered in one unbroken series and tax worked out on each line.Read more E-invoicing softwareEach e-invoice is reported to the IRP from your books, and its IRN and QR code are printed on it.Read more Retail ERP and POSA sale at the counter moves the stock, the cash and the books together.Read more

GST questions people ask.

1.

How do I calculate GST on an amount?

Multiply the amount before GST by the rate and divide by 100. At 18%, GST on ₹10,000 is ₹1,800, so the total is ₹11,800.

— the PrimoERP team

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GST calculator for one amount or a whole bill.

GST calculator

Your GST

How it’s worked out.

One bill, line by line.

What it does not cover.

Which rate your goods or service carry

Exempt goods

Place of supply

Reverse charge

Composition dealers

Exports and SEZ supplies

Cess other than a % of value

Discounts and what goes into the value

TDS and TCS under GST