GST Calculator
Add GST to a price or extract it from a GST-inclusive amount, with the CGST/SGST or IGST split for any rate.
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How to use GST Calculator
- 1
Open GST Calculator on this page. It loads right in your browser.
- 2
Add your file, text or values and adjust the settings.
- 3
Copy the result or download it. Nothing is uploaded or stored.
How to use it: GST Calculator
This GST calculator works both ways. Use Add GST when you have a net price and want the invoice total, or Remove GST when you have a GST-inclusive price and need the taxable value and the tax inside it.
Pick a rate with one tap: 0.25%, 3%, 5%, 18% or 40% under the current slabs, plus 12% and 28% for older invoices, or type any custom rate. For an intra-state sale the tax is split equally into CGST and SGST; for an inter-state sale it is shown as IGST.
How to use it
- Choose Add GST (price before tax) or Remove GST (price including tax).
- Enter the amount and the quantity.
- Tap the GST rate or type a custom one.
- Choose intra-state (CGST + SGST) or inter-state (IGST) and copy the breakdown.
How it is calculated
Add GST: GST = net × rate ÷ 100, total = net + GST. Remove GST: net = gross ÷ (1 + rate/100), GST = gross − net. For intra-state supplies CGST and SGST are each half of the GST.
Worked example
A laptop is sold for ₹50,000 before tax at 18% GST. GST is ₹9,000 and the invoice total ₹59,000; within the same state that is ₹4,500 CGST plus ₹4,500 SGST. If a shop quotes ₹11,800 including 18% GST, the taxable value is ₹10,000 and the GST inside it ₹1,800.
Who uses it
- Shop owners and freelancers preparing invoices
- Buyers checking the tax inside an inclusive price
- Accountants splitting CGST, SGST and IGST
- Students learning GST calculations
Tips
- Most goods and services now fall under 5% or 18%; 40% applies to luxury and sin goods. Check the rate for your HSN or SAC code.
- On B2B invoices show the taxable value and each tax separately: the breakdown here can be copied straight in.
- When removing GST, never just subtract the rate from the total: 18% of ₹1,180 is not the tax inside it.
Free, private and instant: every calculation runs in your browser, nothing is uploaded or stored, and there is no sign-up or limit. Related calculators: VAT calculator, discount calculator, percentage calculator.
Features
- Add or remove GST in one click
- CGST + SGST or IGST split
- Current slabs plus custom rates
- Quantity support for invoices
- Copyable tax breakdown
Frequently asked questions
How do I calculate GST on an amount?
Multiply the amount by the GST rate and divide by 100, then add it to the amount. For ₹1,000 at 18%, GST is ₹180 and the total ₹1,180.
How do I remove GST from a total?
Divide the GST-inclusive total by (1 + rate/100). For ₹1,180 at 18%: 1,180 ÷ 1.18 = ₹1,000 net, so the GST is ₹180.
What is the difference between CGST, SGST and IGST?
On a sale within one state the GST is split equally into Central GST and State GST. On a sale between states the whole amount is charged as Integrated GST.
What are the current GST rates?
After the 2025 reform the main slabs are 5% and 18%, with 40% for luxury and sin goods and special rates such as 0.25% and 3% for some items. Older invoices may still show 12% or 28%.
Is the GST calculator accurate for invoices?
Yes, it calculates to the paisa. Rounding rules on invoices may differ by a rupee; follow your accounting software or the GST rules for final rounding.
Is this calculator free and private?
Yes. It is completely free, needs no account and runs entirely in your browser, so the numbers you type are never sent to a server or stored.