GST Calculator

Add or remove GST in seconds. Enter any amount, choose a rate slab, and see the base price, the GST amount, the CGST/SGST split, and the total — for accurate invoicing and quick price checks.

Adding 18% GST to a base of ₹10,000 gives ₹1,800 in GST (₹900 CGST + ₹900 SGST), for a total of ₹11,800.

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How GST is calculated

GST is a percentage of the taxable value of goods or services. When adding GST, the tax is computed on the base price and added to it: GST = Base × Rate / 100. When removing GST from an inclusive amount, the base is recovered as Inclusive × 100 / (100 + Rate), and the difference is the embedded tax.

CGST, SGST and IGST

For sales within the same state, GST is split equally into Central GST (CGST) and State GST (SGST) — an 18% rate becomes 9% CGST and 9% SGST, each shown above. For inter-state transactions, a single Integrated GST (IGST) at the full rate is charged instead and later apportioned between the centre and the destination state.

Who needs to register for GST?

  • Businesses with annual turnover above ₹40 lakh for goods (₹20 lakh for services) in most states.
  • Anyone making inter-state taxable supplies, regardless of turnover.
  • E-commerce operators and those liable under reverse charge.
  • Registered businesses can claim Input Tax Credit on GST paid for business purchases.

Frequently asked questions

What is GST and how is it structured in India?
Goods and Services Tax is a single indirect tax that replaced multiple central and state levies in July 2017. For intra-state sales, GST is split equally into CGST (central) and SGST (state) — so 18% GST means 9% CGST plus 9% SGST. For inter-state sales, an equivalent IGST is charged instead and shared between the centre and states.
What are the GST rate slabs?
India uses a multi-slab structure with the main rates being 5%, 12%, 18%, and 28%. Essentials and unprocessed food are largely exempt or at 5%, standard goods and services sit at 12% or 18%, and luxury or “sin” goods like tobacco and high-end cars attract 28% plus a cess.
What is the difference between adding and removing GST?
Add GST treats your entered amount as the base (pre-tax) price and adds GST on top to give the final invoice value. Remove GST treats your entered amount as the GST-inclusive price (the MRP you paid) and works backwards to reveal the base price and the tax embedded within it.
How do I calculate the base price from a GST-inclusive amount?
Use the formula: Base = Inclusive Amount × 100 / (100 + GST rate). For example, ₹1,180 inclusive of 18% GST has a base of ₹1,000 and ₹180 of GST. Switch this calculator to Remove GST mode to do this automatically.
Who must register for GST?
GST registration is mandatory once your aggregate annual turnover crosses ₹40 lakh for goods (₹20 lakh in special-category states) or ₹20 lakh for services (₹10 lakh in special-category states). Registration is also compulsory regardless of turnover for inter-state suppliers, e-commerce sellers, and those liable under reverse charge. Smaller businesses can register voluntarily to claim input tax credit.
What is input tax credit (ITC)?
Input tax credit lets a registered business set off the GST it paid on purchases against the GST it collects on sales, so tax is effectively paid only on the value added. For example, if you collect ₹18,000 GST on sales and paid ₹10,000 GST on inputs, you remit only ₹8,000. ITC can be claimed only on business purchases with a valid tax invoice, and is blocked on certain items like personal expenses.
What is the GST composition scheme?
The composition scheme lets small businesses with turnover up to ₹1.5 crore (₹75 lakh in special-category states) pay GST at a low flat rate — about 1% for traders and manufacturers, 5% for restaurants, and 6% for eligible service providers — on turnover instead of regular rates. The trade-off is that they cannot collect GST from customers or claim input tax credit, and must file quarterly. It suits small B2C businesses wanting simpler compliance.
What is reverse charge under GST?
Under reverse charge, the recipient of goods or services pays GST directly to the government instead of the supplier. It applies to specified cases such as services from a goods transport agency, legal services from advocates, and purchases from unregistered dealers in certain situations. The recipient can usually claim the tax paid under reverse charge as input tax credit, subject to conditions.

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The results shown are estimates for illustration only, based on the inputs and assumptions you provide. Actual returns, interest, and tax depend on market conditions, prevailing rates, and applicable laws, which change over time. This is not investment, tax, or financial advice — please consult a qualified advisor before making decisions.

GST amount
₹1,800
Total
₹11,800