Goods and Services Tax (GST) is India's unified indirect tax that replaced VAT, service tax, excise duty, and multiple other taxes. Our GST calculator lets you compute the GST amount on any transaction whether adding GST to a base price (GST-exclusive) or extracting the base price from a GST-inclusive amount.
What Is a GST Calculator?
A GST calculator is a tool that computes the tax amount, pre-GST price, and total GST-inclusive price for any transaction.
It handles both scenarios: (1) Add GST you know the base price and want the final invoice amount; (2) Remove GST you know the GST-inclusive amount and want to extract the original base price.
It also splits the GST into CGST and SGST (for intra-state) or shows IGST (for inter-state) essential for GST invoice preparation.
How to Calculate GST on an Invoice
Adding GST: Invoice Total = Base Price × (1 + GST Rate/100).Example: ₹10,000 service at 18% GST = ₹10,000 × 1.18 = ₹11,800.GST amount = ₹1,800.
Removing GST (reverse calculation): Base Price = Inclusive Amount ÷ (1 + GST Rate/100).Example: ₹11,800 inclusive at 18% = ₹11,800 ÷ 1.18 = ₹10,000 base.GST = ₹1,800.
For intra-state: CGST = SGST = ₹900 each.
For inter-state: IGST = ₹1,800.
Example GST Calculation
CGST (9%) = ₹4,500. SGST (9%) = ₹4,500. Total invoice = ₹59,000. Buyer can claim ₹9,000 ITC. Total bill = ₹840. No ITC available on restaurant GST for most businesses. Construction Material (28% GST): Base ₹1,00,000. GST = ₹28,000. CGST = SGST = ₹14,000 each. Total = ₹1,28,000.
GST Rate Slabs in India
India uses a multi-rate GST structure: 0% (essential goods food grains, fresh vegetables), 5% (household necessities, economy transport), 12% (processed food, computers), 18% (most goods and services, restaurants, telecom), and 28% (luxury goods cars, tobacco, aerated drinks).
Gold and precious metals attract 3%; rough diamonds 0.25%.
Petroleum products are currently outside GST.
CGST, SGST, and IGST Understanding the Split
GST has three components: CGST (Central GST) and SGST (State GST) for intra-state transactions each is half the applicable GST rate.
IGST (Integrated GST) applies on inter-state transactions and imports.
For example, 18% GST on an intra-state sale = 9% CGST + 9% SGST.On inter-state sales, the full 18% is collected as IGST by the central government, which then transfers the state's share.
Tips for GST Compliance
- Always verify the correct HSN/SAC code for your goods or services the GST rate depends on it.
- File GSTR-1 (outward supply) and GSTR-3B (monthly return) on time to avoid late fees of ₹25–₹50/day.
- Reconcile your GSTR-2B (auto-generated ITC statement) monthly to claim correct input tax credit.
- For new businesses, register for GST before crossing the threshold voluntary registration is possible below ₹40L and gives ITC benefits.
- Use the government's official GST portal (gst.gov.in) for filing, not third-party portals.
Steps to Use the GST Calculator
- Enter Base Cost Specify the value based on your financial estimates or requirements.
- Adjust GST Slab Rate (%) Specify the value based on your financial estimates or requirements.
- View Results Review the instant breakdown of calculations, interest splits, or final wealth estimates dynamically displayed.
Advantages of Using the GST Calculator
- Reverse Calculation Easily extract the original base price from a GST-inclusive product price.
- CGST/SGST Split Automatically compute state-central tax splits or interstate IGST details.
- Invoice Preparation Get exact tax amounts needed to prepare compliant GST bills for clients.
- Slab Compatibility Quickly compute calculations across standard rates (5%, 12%, 18%, 28%).
Frequently Asked Questions
Who needs to register for GST?
Businesses with annual turnover above ₹40 lakh (goods) or ₹20 lakh (services) must register. In special category states, thresholds are lower. E-commerce sellers and inter-state suppliers must register regardless of turnover.
Is GST applicable on rent?
Residential rent paid by individuals is exempt from GST. Commercial rent (shops, offices) attracts 18% GST if the landlord's turnover exceeds the GST threshold.
What is the GST rate on restaurant bills?
Standard restaurants charge 5% GST without ITC. Restaurants in 5-star hotels (or room tariff above ₹7,500/night) charge 18% GST with ITC. Takeaway and delivery are also taxed at 5%.
Is there GST on health insurance premiums?
Yes. Health insurance premiums attract 18% GST. The full premium (including GST) qualifies for Section 80D deduction up to the applicable limits.
Can individuals claim GST refunds?
Non-registered consumers generally cannot claim GST refunds as they are not part of the GST chain. Only registered businesses can file for refunds typically in cases of excess ITC or exports.
What is the composition scheme under GST?
Small businesses with turnover up to ₹1.5 crore (₹75L for services) can opt for the composition scheme pay a fixed GST rate (1% for traders, 5% for restaurants, 6% for service providers) without collecting GST from customers or claiming ITC. Simplified returns and lower compliance burden make it attractive for small businesses.
What is reverse charge mechanism (RCM)?
Under RCM, the recipient of goods or services is liable to pay GST directly to the government instead of the supplier.
What is Input Tax Credit (ITC)?
ITC allows businesses to reduce the tax they have paid on purchases from the tax they collect on sales, preventing cascading taxes.