What is GST and what replaced it?

GST (Goods and Services Tax), launched on July 1, 2017, is India's unified indirect tax system that replaced a complex web of over 17 central and state taxes including Central Excise Duty, Service Tax, VAT, CST, Entry Tax, Entertainment Tax, and Luxury Tax. The 'One Nation, One Tax' reform eliminated the cascading effect of multiple taxes (tax on tax) that previously inflated prices. GST has four main rate slabs: 5% (essential goods and services), 12% (processed foods, standard goods), 18% (most services, standard manufactured goods), and 28% (luxury goods, tobacco, automobiles, aerated beverages). A 0% rate covers essential food items and healthcare.

What is the difference between CGST, SGST, and IGST?

For intra-state transactions (buyer and seller in the same state), GST is split equally into two halves: CGST (Central Goods and Services Tax), which goes to the Union Government, and SGST (State Goods and Services Tax), which goes to the state government. So 18% GST on an intra-state sale = 9% CGST + 9% SGST. For inter-state transactions (buyer and seller in different states), only IGST (Integrated Goods and Services Tax) applies at the full rate (18%), and this revenue is shared between the central and destination state governments. For all practical calculations - adding or removing GST - the formula is the same regardless of whether it is CGST+SGST or IGST.

How do I add GST to a base price?

GST Amount = Base Price x GST Rate / 100. Total (inclusive price) = Base Price + GST Amount. Example: ₹1,000 base price + 18% GST: GST = ₹1,000 x 18/100 = ₹180. Total = ₹1,180. In business invoicing, you must show the base price, GST rate, and GST amount separately. If you are the seller and GST-registered, you collect this GST from your customer and remit it to the government monthly or quarterly. As a buyer, if you are GST-registered, you can claim this as Input Tax Credit to offset against your own GST liability.

How do I extract (remove) GST from a GST-inclusive price?

Base Price = Inclusive Price x 100 / (100 + GST Rate). GST Amount = Inclusive Price - Base Price. Example: ₹1,180 inclusive price with 18% GST: Base = ₹1,180 x 100/118 = ₹1,000. GST = ₹1,180 - ₹1,000 = ₹180. This is the correct formula - a common mistake is calculating ₹1,180 x 18% = ₹212.40 (wrong - this applies 18% to the inclusive price, not the exclusive base). When you receive a GST-inclusive invoice and need to know the base price for accounting, always use the division formula, not the multiplication formula.

Which items have 0% GST and which have 28%?

0% (exempt): fresh fruits and vegetables, unbranded food grains, milk, eggs, fresh fish and meat, bread (unbranded), contraceptives, books, healthcare services, and basic education services. 5%: packaged food items, tea, coffee, edible oils, domestic LPG, railway tickets (non-AC). 12%: processed foods, butter, cheese, computers, mobile phones, processed meat. 18%: most services (restaurant meals, telecom, banking fees, most manufactured goods, IT services, hotels). 28%: luxury cars, tobacco, pan masala, aerated drinks, casinos, and high-end personal care products. A 28% cess applies additionally on top of the 28% base on items like automobiles and tobacco.

What is Input Tax Credit (ITC) in GST?

Input Tax Credit allows GST-registered businesses to offset the GST they paid on purchases against the GST they collect on sales. Example: a manufacturer buys raw materials worth ₹1 lakh + ₹18,000 GST (18%). They sell finished goods for ₹1.5 lakh + ₹27,000 GST. Instead of paying ₹27,000, they can claim ₹18,000 ITC and pay only ₹9,000 net GST to the government. This eliminates the cascading 'tax on tax' that existed before GST. ITC is available only if: the supplier has filed their GST returns and paid the tax, you hold a valid GST invoice, and goods/services are used for business purposes. ITC is not available on personal expenses or exempt goods.

What is the GST composition scheme and who qualifies?

The GST composition scheme lets small businesses with annual turnover up to Rs. 1.5 crore (Rs. 75 lakh for service providers) pay a flat low rate of tax and file quarterly returns instead of monthly. Traders pay 1% of turnover (0.5% CGST + 0.5% SGST), manufacturers pay 2%, and restaurants pay 5%. The scheme radically simplifies compliance - no input tax credit, no detailed invoice-by-invoice filing, just quarterly returns with a flat rate. The trade-off is that composition dealers cannot collect GST from customers (since they pay the tax themselves as a turnover percentage) and cannot claim ITC. This makes the scheme unsuitable for businesses that sell to GST-registered companies (who need ITC). It is ideal for small retailers, local restaurants, and traders who primarily serve end consumers.

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GST Calculator

Add or remove GST from any amount. Instantly get CGST, SGST, and total breakup for 5%, 12%, 18%, and 28% rates.

About the GST Calculator

GST (Goods and Services Tax), introduced on 1 July 2017, replaced over a dozen central and state taxes - excise duty, service tax, VAT, CST, octroi - with a single unified tax structure. India adopted a dual-structure GST: for transactions within a state, the tax splits equally into CGST (collected by the Centre) and SGST (collected by the state). For transactions across state borders, a single IGST is levied, which the Centre distributes to the destination state.

There are five GST slabs: 0% for exempt essentials like fresh vegetables, milk, and healthcare; 5% for basic goods like packaged food and economy transport; 12% for processed foods and some medicines; 18% for most services, electronics, and FMCG; and 28% for luxury goods, tobacco, and aerated drinks. A GST Cess applies on top of the 28% slab for certain items like luxury cars and tobacco.

This calculator handles both scenarios you encounter in practice: adding GST to a quoted base price before raising an invoice (exclusive mode), and extracting the GST component from a price that already includes it (inclusive mode). Use it to verify bills, prepare invoices, or check whether a vendor has charged the right rate.

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Add or Extract GST

Switch between Exclusive mode (add GST to a base price) and Inclusive mode (extract GST already embedded in a total amount).

Core feature

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CGST + SGST + IGST

See the full tax breakup. Intra-state supply splits into equal CGST and SGST. Inter-state supply uses a single IGST equal to the full rate.

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All 5 GST Slabs

Covers 0% (exempt essentials), 5%, 12%, 18%, and 28% - with product examples for each slab so you can verify the correct rate at a glance.

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Shareable Calculations

All inputs are encoded in the URL. Share a pre-filled GST calculation with a client or team member via the Share button.

GST Calculation

Add GST: Final Price = Base Price × (1 + GST%/100) · Extract GST: Base Price = Inclusive Price / (1 + GST%/100)

CGST = GST% / 2 of base price (intra-state) · SGST = GST% / 2 of base price (intra-state) · IGST = Full GST% of base price (inter-state) · GST Amount = Final Price - Base Price

Worked Example

A Delhi business buys office furniture (₹85,000 exclusive) from a Mumbai supplier - inter-state purchase at 18% GST

Base Amount:₹85,000

GST Rate:18% (furniture - HSN 9403)

Supply Type:Inter-state (Delhi buyer, Mumbai seller)

IGST @ 18% = ₹15,300 · Total invoice = ₹1,00,300. The Delhi business can claim ₹15,300 as Input Tax Credit in their GSTR-3B, making the net cost ₹85,000. If the supplier were also in Delhi, CGST (9%) = ₹7,650 + SGST (9%) = ₹7,650 = same ₹15,300 total, split between Centre and state.

Tips & Insights

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The same product can attract different GST rates depending on its form. Unpackaged wheat flour is 0%; branded packaged flour is 5%. Loose milk is exempt; flavoured milk is 12%. Always verify the exact HSN code for your product at cbic-gst.gov.in before raising an invoice - a wrong rate classification can trigger a demand notice.
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Restaurants charge 5% GST uniformly since the AC/non-AC distinction was removed. The exception: restaurants inside hotels with room tariffs above ₹7,500 per night charge 18% GST. Swiggy and Zomato collect GST as e-commerce operators and remit it directly - individual restaurant owners on these platforms do not collect GST themselves.
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Input Tax Credit (ITC) is GST's biggest business benefit. Every rupee of GST you pay on purchases for your business reduces your GST liability on sales. A registered business buying ₹10L of goods at 18% GST gets ₹1.8L ITC. Always demand a valid GST invoice with your GSTIN - a bill without your GSTIN cannot be used for ITC.
4
Reverse Charge Mechanism (RCM) makes the buyer liable to pay GST directly to the government in specific cases: purchases from unregistered suppliers above threshold, legal services from individual advocates, security services, and GTA (goods transport agency) freight. Many businesses overlook RCM and receive audit notices - check whether your vendor is RCM-applicable.
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Under-construction property attracts 5% GST (without ITC benefit) on the property value excluding land. Once the builder obtains a completion certificate, the sale is GST-exempt. If you are buying a flat before possession, GST applies to every instalment. For a ₹70L flat (land = 30% = ₹21L), GST applies on ₹49L at 5% = ₹2.45L extra.
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Composition scheme lets businesses with turnover up to ₹1.5 crore pay a flat 1-5% tax on turnover instead of regular GST rates. Composition dealers cannot charge GST on invoices and cannot claim ITC - suitable only for small B2C retailers and manufacturers. Service providers have a separate composition rate of 6%.
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Verify supplier GSTIN before making large payments. If a supplier's GSTIN is suspended or if they fail to file their returns, you cannot claim ITC on purchases from them even if you paid the GST amount. The GST portal now auto-blocks ITC claims for purchases from non-compliant suppliers. Check at gstin.gov.in or in your GSTR-2B before payment.
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GST refunds are available when ITC accumulates beyond your output liability - common for exporters (who sell at 0% GST but pay GST on inputs) and businesses in inverted duty structure (input tax rate higher than output rate). File refund applications in GSTR-9; unclaimed refunds lapse two years from the end of the relevant tax period.

Why this matters for you

GST touches every rupee spent in India - a ₹500 restaurant bill, a ₹5,000 phone repair, a ₹50,000 laptop, a ₹50 lakh flat. Understanding how GST is calculated prevents two expensive mistakes consumers make: being overbilled by vendors who inflate the base price before adding GST, and not realising that the quoted price may already include GST (making 'add 18%' on top a double-charge).

For the 1.4 crore GST-registered businesses in India, correct GST calculation is a compliance requirement with real financial consequences. A business that collects 18% GST but classifies a product at 12% faces the 6% difference as a demand plus 18% interest per annum. The GST department's AI-driven invoice matching across GSTR-1 and GSTR-3B filings makes classification errors far easier to detect than under the old VAT regime.

The intra-state vs inter-state distinction matters beyond just accounting. CGST and SGST accrue to different governments; IGST collected at the Centre is later apportioned to destination states. For businesses selling across India, getting this wrong means depositing tax to the wrong head - which requires rectification filings, interest calculations, and often a CA's intervention. This calculator makes the math instant so you can focus on getting the categorisation right.