GST Calculator India 2025: Add/Remove GST, CGST+SGST vs IGST, All Slab Rates
GST (Goods and Services Tax) replaced India's complex indirect tax system in July 2017. Whether you're a business owner issuing invoices, a freelancer calculating taxes, or a consumer wanting to verify charges, understanding how GST is calculated prevents costly mistakes. This guide covers every scenario.
Try GST Calculator Free →GST Calculation: Adding GST to a Base Price
GST Amount = Base Price × (GST Rate / 100). Total Price = Base Price + GST Amount. Example: ₹10,000 base price with 18% GST → GST = ₹1,800 → Total = ₹11,800. This is the "exclusive" or "add GST" mode used when you know the pre-tax price.
Removing GST from an Inclusive Price
Original Price = Inclusive Price / (1 + GST Rate/100). GST Amount = Inclusive Price − Original Price. Example: ₹11,800 inclusive of 18% GST → Base = ₹11,800/1.18 = ₹10,000 → GST = ₹1,800. Use this when a price "includes GST" and you need the breakup.
CGST + SGST vs IGST
For intra-state transactions (buyer and seller in same state): GST splits equally into CGST (Central) + SGST (State), each at half the GST rate. For inter-state transactions (different states): Full GST is charged as IGST (Integrated). Example at 18%: Intra-state = 9% CGST + 9% SGST. Inter-state = 18% IGST.
GST Rate Slabs in India
0% — Essential items: food grains, fresh vegetables, milk, eggs. 5% — Mass consumption items: packaged food, transport services, restaurants. 12% — Processed food, computers, mobiles, business class travel. 18% — Most services, electronics, restaurants above ₹7,500/day. 28% — Luxury items: cars, tobacco, aerated drinks, high-end goods.
GST Registration Threshold (2025)
Businesses with annual turnover above ₹40L (goods) or ₹20L (services) must register for GST. Special category states have a lower ₹20L/₹10L threshold respectively. Voluntary registration is allowed below the threshold to claim Input Tax Credit (ITC).
Input Tax Credit (ITC)
Registered businesses can claim ITC — offsetting GST paid on purchases against GST collected on sales. ITC is only available on business purchases, not personal expenses. The net GST payable = GST collected − ITC. This prevents the cascading tax-on-tax effect of the old system.
Frequently Asked Questions
What is the GST rate on services?⌄
Most services are taxed at 18% GST. Exceptions include financial services (exempt), healthcare (exempt), education (exempt), and restaurants (5% without ITC or 18% with ITC).
Do I need GST registration as a freelancer?⌄
If your annual income from services exceeds ₹20L (₹10L for special category states), GST registration is mandatory. Below this threshold, registration is voluntary but allows you to issue proper GST invoices and claim ITC.
What is Reverse Charge Mechanism (RCM)?⌄
Under RCM, the recipient of goods/services pays GST instead of the supplier. This applies to specific categories like legal services from advocates, goods transport agencies, and imports.
How is GST different from VAT?⌄
VAT was a state-level tax with cascading effects (tax on tax). GST replaced it with a single unified tax across India, with ITC available throughout the supply chain, eliminating the cascading effect.