GST FAQ
What is GST in India?
GST (Goods and Services Tax) is a unified indirect tax that came into effect on 1 July 2017, replacing VAT, service tax, excise duty, and several other state and central taxes. It applies to most goods and services sold in India.
Most items fall into one of five rate slabs: 0%, 5%, 12%, 18%, 28%. A compensation cess applies to certain luxury and sin goods on top.
What's the difference between CGST, SGST, and IGST?
CGST + SGST apply to intra-state transactions (supplier and recipient in the same state). The GST is split equally — half to the centre (CGST), half to the state (SGST).
IGST applies to inter-state transactions. The full amount is collected by the centre, then shared with the destination state.
Example on 18% GST: intra-state shows 9% CGST + 9% SGST; inter-state shows 18% IGST.
What is the GST registration limit?
Mandatory GST registration thresholds (annual turnover):
- Goods: ₹40 lakh (₹20 lakh in special category states)
- Services: ₹20 lakh (₹10 lakh in special category states)
Businesses below the threshold can register voluntarily to claim input tax credit. The composition scheme has separate rules with lower thresholds and limited rate options.
How do I calculate GST on a price?
Adding GST (when you have the net amount):
GST = base × rate / 100
Total = base + GST
Example: ₹10,000 at 18% → GST = ₹1,800, Total = ₹11,800.
Removing GST (when you have the inclusive total):
Base = total ÷ (1 + rate / 100)
Example: ₹11,800 incl. 18% → Base = ₹10,000, GST = ₹1,800.
The GST calculator on the home page handles both modes.
What is "place of supply"?
Place of supply determines whether a transaction is intra-state (CGST+SGST) or inter-state (IGST). For goods, it's typically the delivery location. For services it varies by service type. Same-state delivery → intra-state. Different state → inter-state.
What is reverse charge mechanism (RCM)?
Under reverse charge, the recipient pays GST instead of the supplier. It applies to specific notified categories — for example, services from a goods transport agency — and to certain purchases from unregistered suppliers. The recipient pays GST directly and can usually claim it back as input tax credit.
What is input tax credit (ITC)?
ITC lets a registered business offset the GST it has paid on purchases (inputs) against the GST it owes on sales (outputs). If you collect ₹18,000 GST from customers and have paid ₹10,000 GST on purchases, you remit only ₹8,000 to the government. ITC is subject to conditions, including matching supplier filings.
Which GST rate applies to services?
Most services in India are taxed at 18% — the default for professional services, IT, marketing, consulting, etc. Other rates exist:
- 5% — transport, restaurants without AC, low-cost services
- 12% — some construction-related services
- 18% — most services (default)
- 28% — luxury services (certain hotel rates, some entertainment)
Always look up the SAC (Service Accounting Code) for your specific service.
How often do I need to file GST returns?
Most regular taxpayers file:
- GSTR-3B — monthly summary return
- GSTR-1 — monthly or quarterly outward supplies
- GSTR-9 — annual return
Under the QRMP scheme, GSTR-3B is quarterly with monthly tax payments. Composition taxpayers file CMP-08 quarterly.
Is GSTBox accurate? Can I use the output for filing?
The math is correct — GSTBox uses standard GST formulas and the current rate slabs. But the correct rate for your specific product or service depends on its HSN/SAC code, place of supply, and any applicable exemptions. Always verify against current CBIC notifications and consult a CA before filing. GSTBox is a quick-calc tool, not a tax adviser.
Is GSTBox really free?
Yes. No signup, no email capture, no premium tier. The calculator never shows ads. Supporting articles may show occasional ads.
Does GSTBox work offline?
Once the page has loaded, the calculator works without internet. Everything runs in your browser. You can save the page locally and use it on a flight or train if needed.