18% GST Calculator — India's Most Common Tax Rate — FY 2026-27
18% is the most common GST slab in India — applies to almost all services (consulting, software, telecom, insurance, banking, professional), restaurant dining, electronic goods, and branded packaged foods. Our calculator works both forward (add 18% to base) and reverse (extract 18% from inclusive MRP), splits into CGST+SGST for intra-state and IGST for inter-state.
Compute your numbers → GST Calculator
Use the full GST Calculator for interactive computation with your exact inputs. This page covers the specific context + rules for your query intent.
Key rules at a glance
- 18% GST on almost all services
- Forward + reverse calculation
- Auto CGST 9% + SGST 9% split (intra-state)
- IGST 18% for inter-state
- No composition scheme under 18%
What falls under 18% GST?
ALMOST ALL SERVICES: consulting, software, SaaS, telecom, internet, banking fees, insurance premium (for life/non-life beyond first-year), freelancer services, design/marketing/advertising, event management, legal services (to non-body-corporate), engineering, architecture. GOODS: electronics (TV, phone, laptop, refrigerator), branded packaged foods, cosmetics, most automotive parts, paint, cement.
18% forward formula
GST amount = base × 18 / 100. Total inclusive = base × 1.18. For ₹1,000 consulting invoice: GST = ₹180, total = ₹1,180. Intra-state: ₹90 CGST + ₹90 SGST (same customer pays ₹180 split administratively). Inter-state: ₹180 IGST.
18% reverse formula
Base = inclusive / 1.18. For ₹1,180 client payment inclusive of 18% GST: base = 1180 / 1.18 = ₹1,000. GST = ₹1,180 − ₹1,000 = ₹180. Common use: freelancer contractor sees net client wire of ₹1,180 and needs to book ₹1,000 as revenue + ₹180 as GST payable.
18% GST Calculator — FAQ
What goods/services have 18% GST in India?
Most services (consulting, SaaS, telecom, freelance, professional), restaurant dining (non-composition), branded foods, electronics, cosmetics, many automotive parts. The GST Council adjusts slabs periodically — verify the current HSN/SAC rate on cbic.gov.in before issuing high-value invoices.
How do I calculate 18% GST on ₹1000?
Forward: GST = ₹1000 × 18/100 = ₹180. Total inclusive = ₹1,180. Reverse (if ₹1180 is inclusive): base = 1180/1.18 = ₹1,000; GST = ₹180. Same numbers, opposite direction.
Is 18% GST inclusive or exclusive by default?
B2B: typically EXCLUSIVE — invoice shows base + GST as separate line items. B2C consumer: can be either; check invoice. MRP on retail products is ALWAYS inclusive of GST by law. Always clarify with client before invoicing if unclear.
Can the client claim ITC on 18% GST I charge?
Yes, if client is GST-registered and the supply is used for business. Show GSTIN + HSN/SAC + CGST/SGST/IGST split clearly on invoice. Client matches your GSTR-1 to their GSTR-2A/2B and claims ITC in GSTR-3B. Most of your B2B revenue will be ITC-claimable.
What is the threshold to register for GST at 18%?
₹20 lakh annual turnover (₹10 L for special category states: NE + hilly states). Service providers must register if turnover crosses this regardless of GST rate charged. Specified services (e-commerce, cross-border) need registration from ₹1.
Related tax calculators
GST Calculator
Main interactive calculator.
New Regime Tax Calculator
New Regime Income Tax Calculator for FY 2026-27.
Old Regime Tax Calculator
Old Regime Income Tax Calculator for FY 2026-27.
Senior Citizen Tax Calculator
Senior citizen income tax calculator FY 2026-27.
Reverse GST Calculator
Reverse GST Calculator — extract base price + tax from an MRP / GST-inclusive amount.