GST Invoice Calculator India — Final Invoice with GST
CGST · SGST · IGST Breakdown — Invoice, Reverse GST & Business Summary
A GST-compliant invoice must include: GSTIN of both parties, place of supply, HSN/SAC code, taxable value, applicable GST rate and amount (CGST+SGST or IGST), and total invoice value. Errors in invoice lead to ITC rejection for buyers and GST notices for sellers. This calculator ensures your invoice amounts are computed correctly with proper CGST/SGST/IGST split based on supply type.
🧾 GST Calculator
How to Use GST Calculator India
Enter the base amount, select the GST rate slab (5%, 12%, 18%, 28%), choose Exclusive (add GST to amount) or Inclusive (extract GST from total), and select whether it's an Intra-state (CGST + SGST) or Inter-state (IGST) transaction. Get instant breakup — no login, no install.
How GST Calculator Works — Formula
GST Exclusive: GST Amount = Base × Rate/100 · Total = Base + GST
GST Inclusive (Reverse): Base = Total ÷ (1 + Rate/100) · GST = Total − Base
CGST & SGST = GST Amount ÷ 2 each (for intra-state transactions).
Example: ₹10,000 base at 18% → GST = ₹1,800 · CGST = ₹900 · SGST = ₹900 · Total = ₹11,800.
CGST vs SGST vs IGST — What's the Difference?
CGST (Central GST) goes to Central Government. SGST (State GST) goes to State Government. Both are charged on intra-state transactions (seller and buyer in the same state), each at half the total GST rate. IGST (Integrated GST) is charged on inter-state transactions and goes entirely to the Central Government, which then distributes to the destination state.
Real-Life GST Examples India 2025
🛒 Grocery (Milk, fresh vegetables): 0% GST — exempt essentials.
💊 Medicines, life-saving drugs: 5% GST — reduced rate for healthcare.
📱 Mobile phones, computers: 12% GST — standard electronics rate.
🍕 Restaurant services, AC restaurants: 5% or 18% GST — varies by type.
🏠 Under-construction flats: 5% GST (affordable) or 12% (premium).
🚗 Luxury cars: 28% GST + 12–22% Cess — highest tax bracket.
Frequently Asked Questions
What are mandatory fields in a GST invoice?
Mandatory: (1) Supplier name, address, GSTIN. (2) Invoice number & date. (3) Recipient details (GSTIN for B2B). (4) Place of supply. (5) HSN/SAC code (mandatory for turnover >₹5Cr, optional for others). (6) Item description, quantity, value. (7) Tax rate, CGST/SGST or IGST amounts. (8) Total invoice value in words.
What is the time limit to issue GST invoice?
Goods: invoice must be issued before or at time of removal of goods. Services: within 30 days of service completion (45 days for banking/NBFC). For continuous supply of services (subscription, rent): at agreed billing cycle but before due date. Delay attracts penalty and bars ITC claim for buyer.
Can I issue a GST invoice without GSTIN?
If supplier is unregistered (turnover below threshold): no GST charged, no GSTIN on invoice. Buyer must pay GST under RCM if applicable. If supplier is registered but buyer is unregistered (B2C): issue B2C invoice without buyer GSTIN. For B2B: buyer GSTIN mandatory for ITC claim. Keep records of all B2C invoices.
What is a debit note and credit note in GST?
Debit note: issued by supplier when invoice value needs to increase (price revision up, extra item). Increases GST liability. Credit note: supplier issues when invoice value decreases (return of goods, discount post-supply, price revision down). Reduces GST liability. Both must be reported in GSTR-1. Time limit: before September 30 of next financial year.