GST calculator
Total including GST
₹1,180.00
- Price before GST
- ₹1,000.00
- CGST 9%
- ₹90.00
- SGST 9%
- ₹90.00
- IGST 18%
- ₹0.00
- Total GST 18%
- ₹180.00
₹1,000.00 plus 18% GST is ₹1,180.00.
GST calculator — add or remove GST, with the CGST and SGST split
Type an amount, pick a rate, and say whether the sale is within your state. The price, the GST and the total update as you type, split into CGST and SGST or shown as IGST.
The short answer
To add GST, multiply the price by the rate: ₹1,000 at 18% carries ₹180 of GST — ₹90 CGST and ₹90 SGST within a state, or ₹180 IGST across states — for ₹1,180 in all. To take GST out of a total that already includes it, divide by one plus the rate: ₹1,180 including 18% is ₹1,000 before tax. Taking 18% of the total instead gives ₹212.40, which overstates the tax. The calculator rounds the tax once and then splits it, so CGST and SGST always add up to the GST shown.
Four steps to the right GST
Step 1: Type the amount
Enter the price before tax, or the total if GST is already inside it. Commas and the ₹ sign are fine.
Step 2: Add or remove
Choose A price — add GST, or A total — remove GST when the amount already includes it.
Step 3: Pick the rate
Tap 5%, 18%, 40%, 3%, 0.25% or 0%, or type any other rate up to 40% in the Other box.
Step 4: Read the split
Choose Within my state for CGST and SGST, or To another state for IGST. Copy the breakdown to paste into a bill or a message.
GST on ₹1,000 and more
Each row is what the calculator shows for a sale within your state. Across states, the same GST is charged as IGST instead of the two halves.
| Price before GST | Rate | GST | CGST + SGST | Total |
|---|---|---|---|---|
| ₹1,000 | 5% | ₹50.00 | ₹25.00 + ₹25.00 | ₹1,050.00 |
| ₹1,000 | 18% | ₹180.00 | ₹90.00 + ₹90.00 | ₹1,180.00 |
| ₹1,000 | 40% | ₹400.00 | ₹200.00 + ₹200.00 | ₹1,400.00 |
| ₹2,499 | 18% | ₹449.82 | ₹224.91 + ₹224.91 | ₹2,948.82 |
| ₹1,234.56 | 0.25% | ₹3.09 | ₹1.55 + ₹1.54 | ₹1,237.65 |
The last row is why the split is worked out from the rounded tax: ₹3.09 cannot be halved evenly, so the odd paisa goes to CGST and the two halves still add up to the GST.
Where GST sums go wrong
Never take 18% of a total
The rate was charged on the price, not on the total. Inside an ₹1,180 bill at 18% there is ₹180 of GST — 18/118 of it — not ₹212.40. Choose A total — remove GST and the calculator does that division for you.
Same state or across states
A sale within your own state splits the tax evenly into CGST and SGST. A sale to another state is IGST at the full rate. The total is the same either way.
The odd paisa goes to CGST
₹1,234.56 at 0.25% is ₹3.09 of tax, which cannot be halved evenly. The calculator rounds the tax once and gives the extra paisa to CGST: ₹1.55 CGST and ₹1.54 SGST, adding back to ₹3.09.
Whole rupees for quick quotes
Tick Round to whole rupees to drop the paise. Keep paise for an invoice; whole rupees reads faster when quoting a customer across a counter.
Questions people ask
Anything we've missed?
How do I calculate GST on a price?
Multiply the price by the rate and add it on. ₹1,000 at 18% carries ₹180 of GST, so the total is ₹1,180. In the calculator, type 1000, keep A price — add GST, and pick 18%: it shows the ₹1,180 total with ₹90 CGST and ₹90 SGST.
How do I remove GST from a total?
Divide the total by one plus the rate. ₹1,180 including 18% is ₹1,180 ÷ 1.18 = ₹1,000 before tax, so the GST inside it is ₹180. In the calculator, type 1180, choose A total — remove GST, and pick 18%.
What is the GST formula?
To add GST: GST = price × rate ÷ 100, and total = price + GST. To take it out of a total that already includes it: price = total × 100 ÷ (100 + rate), and GST = total − price. At 18%, ₹1,000 becomes ₹1,180, and ₹1,180 goes back to ₹1,000. The calculator uses this formula and rounds the tax once, to the paisa.
What are the components of GST?
Three: CGST for the centre and SGST for the state, charged half each on a sale within one state, and IGST, charged at the full rate on a sale between states. In a union territory without a legislature the state half is called UTGST; the amount is the same. Understanding which one applies changes only how the tax is split under each head, never the total.
When is it CGST and SGST, and when is it IGST?
CGST and SGST apply, half each, when the seller and the place of supply are in the same state. IGST applies at the full rate when they are in different states. Choose Within my state or To another state.
Which GST rates does it have?
Buttons for 5%, 18% and 40%, the three main slabs since 22 September 2025, plus 3% for gold and jewellery, 0.25% for rough diamonds and 0%. Type any other rate up to 40%, such as 1% or 6% for composition dealers or 12% for an old invoice, in the Other box.
Is anything I type sent anywhere?
No. The calculation runs in your browser and nothing is saved or uploaded. There is no account and nothing to sign in to.
Is this the same as the GST Calculator app?
It uses the same calculation code as the GST Calculator Android app, so both give the same answer to the paisa. The app adds a full keypad, history, HSN and SAC search, a business profile and a GST bill as a PDF to send on WhatsApp, and works offline.
Does it file my GST return?
No. It calculates and informs. It does not file returns, connect to the GST portal or keep accounts, and it is not a government service. Check rates against the CBIC notifications for anything you file.
Guides worth reading
- GST
CGST, SGST or IGST: which one goes on your invoice, and how to split it
Within a state, GST splits into equal CGST and SGST. Across state lines it is one IGST line at the full rate. How to tell which applies, with worked splits.
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GST on gold jewellery: 3%, making charges, and how to check the bill
Gold jewellery carries 3% GST, a rate GST 2.0 left alone. How making charges are taxed, where the 5% rate applies, and how to check a jeweller's bill.
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GST on a restaurant bill: how to check it's charged right
Most restaurants charge 5% GST, as 2.5% CGST and 2.5% SGST. When 18% is right, why service charge is optional, and how to check a bill in thirty seconds.
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