descriptionInvoice + GST Breakdown Calculator
Calculate item-wise GST — CGST/SGST for intra-state, IGST for inter-state with invoice preview
Invoice Items
Tax Computation
Taxable Value = Qty × Price × (1 − Discount%/100)
Intra-state: CGST = SGST = Taxable × Rate/2/100
Inter-state: IGST = Taxable × Rate/100
What is an Invoice GST Calculator?
A GST tax invoice must show the itemwise breakup of price, GST rate applied, and the resulting CGST/SGST (intra-state) or IGST (inter-state) amounts for each line item. For businesses with multiple products attracting different GST rates, preparing accurate invoices is essential for compliance.
A B2B GST invoice must include GSTIN of both parties, HSN/SAC codes, description, quantity, rate, taxable value, and tax amount. For B2C invoices above ₹2.5 Lakhs, the same requirements apply. Incorrect invoicing leads to ITC mismatches and compliance notices.
lightbulb Example Calculation
Scenario: M/s Kumar Electronics (Mumbai, GSTIN registered) sells to a business client in Maharashtra (intra-state): Laptop ₹45,000 (18% GST) + Printer ₹12,000 (18% GST) + USB drives (5 nos.) ₹500 each (12% GST)
1Laptop: Taxable ₹45,000 → CGST 9% = ₹4,050 | SGST 9% = ₹4,050 | Invoice value = ₹53,100
2Printer: Taxable ₹12,000 → CGST ₹1,080 + SGST ₹1,080 | USB: 5×₹500 = ₹2,500 → CGST ₹150 + SGST ₹150
3Total taxable = ₹59,500 | Total CGST = ₹5,280 | Total SGST = ₹5,280 | Grand total = ₹70,060
✓ Result: Kumar Electronics raises an invoice for ₹70,060 — ₹10,560 collected as GST (₹5,280 CGST + ₹5,280 SGST) to be remitted to government.
help_outlineHow to Use the Invoice GST Calculator
- Enter the Item Name and HSN Code for each product or service. HSN codes determine the applicable GST rate — e.g., 8471 for computers, 9401 for furniture.
- Enter Quantity, Unit Price, and any Discount % for each line item. Discount is applied before GST calculation — GST is charged on the net taxable value (after discount).
- Select the GST Rate (0%, 5%, 12%, 18%, or 28%) and Supply Type (Intra-state for same-state transactions → CGST+SGST; Inter-state for cross-state transactions → IGST).
- Click Add Item Row to add more products to the same invoice. Different items can have different GST rates — each is calculated separately.
- Click Calculate Invoice to see the item-wise breakdown, total CGST/SGST/IGST, grand total, and an invoice preview showing the GST-compliant format.
Benefits
- Calculate multi-rate invoices instantly — when different items attract different GST rates (e.g., stationery 12%, electronics 18%)
- Auto-splits GST into CGST+SGST or IGST based on supply type — no manual calculation
- HSN code tracking helps verify correct GST rate applicability for each product
- Discount is deducted before GST calculation — ensures accurate taxable value and correct tax amount
- Invoice preview layout follows GSTN-compliant format — useful as a reference for your billing software
Key Terms
- CGST (Central GST)
- Half the GST rate, collected by the Central Government for intra-state (same-state) supply. For 18% GST, CGST = 9% of taxable value.
- SGST (State GST)
- Other half of GST rate, collected by the State Government for intra-state supply. CGST + SGST = total GST for same-state transactions.
- IGST (Integrated GST)
- Full GST rate collected for inter-state (cross-state) supply. No split into CGST/SGST. IGST is shared between Centre and destination state by the government.
- HSN Code
- Harmonised System of Nomenclature — 6–8 digit product classification code determining GST rate. Mandatory on B2B invoices for businesses with turnover above ₹5 Crore (6-digit HSN required).
- Taxable Value
- Invoice value after deducting discount — the base for GST calculation. GST is charged on taxable value, not on the full invoice amount before discount.
quizFrequently Asked Questions
When should I use CGST/SGST vs IGST — how do I determine intra-state vs inter-state?
Use CGST + SGST (intra-state) when the supplier and buyer are in the same state or union territory — both GSTINs have the same 2-digit state code. Use IGST (inter-state) when the supplier and buyer are in different states. For example, a Mumbai supplier (GSTIN starting 27) selling to a Delhi buyer (GSTIN starting 07) charges IGST. Place of Supply rules determine this: for goods, it's the delivery location; for services, it's where the recipient is registered. Getting this wrong leads to wrong tax credit for the buyer and legal complications for the supplier.
How is GST calculated on discounts — is GST charged on MRP or sale price?
GST is charged on the taxable value — which is the price after deducting any discount that is mentioned on the invoice. For example: item MRP ₹1,000, discount 10% → taxable value = ₹900 → GST 18% = ₹162. Total invoice value = ₹1,062. The discount must be shown on the invoice to reduce the tax base. Post-sale discounts (credit notes) where the discount is given after the invoice has been raised require a credit note with GST adjustment — the original invoice GST cannot be retrospectively changed without a formal credit note process.
What is an HSN code and how do I find the right HSN for my product?
HSN (Harmonised System of Nomenclature) is an internationally standardised 6–8 digit code for classifying goods. India uses 8-digit HSN codes. The GST Council has mapped GST rates to specific HSN codes — so the correct HSN determines the correct tax rate. Find your product's HSN: (1) CBIC HSN search tool at cbic-gst.gov.in; (2) GST rate schedule (government notification); (3) Ask your CA or GST practitioner; (4) Look at previous invoices from your supplier (they're required to mention HSN). Mandatory for: businesses with turnover above ₹5 Crore (4-digit HSN for ₹1.5–5 Crore, optional below ₹1.5 Crore).
Is GST charged on freight/delivery charges in a B2B invoice?
Yes — freight charges billed on the same invoice are subject to GST. Typically, freight is taxed at the same GST rate as the goods (if bundled as a single supply). If freight is mentioned separately, it may attract 5% GST (transport of goods by road). For B2B transactions where a transporter carries goods under a goods transport agency arrangement, reverse charge may apply — the recipient (buyer) pays GST on freight. For B2C home delivery, e-commerce sellers add freight and charge GST on the combined amount at the goods' GST rate. Always show freight line items separately in invoices for clarity.
What are the mandatory fields in a GST-compliant tax invoice?
A GST tax invoice must include: (1) Supplier GSTIN and name/address; (2) Buyer GSTIN and name/address (B2B); (3) Invoice number and date; (4) HSN/SAC codes; (5) Description of goods/services; (6) Quantity and unit; (7) Taxable value per item; (8) GST rate (CGST/SGST or IGST rate); (9) Tax amount (CGST/SGST or IGST separately); (10) Total invoice value; (11) Place of supply. For invoices above ₹50,000 to unregistered persons: buyer's name and address also required. E-invoicing (IRN + QR code) is mandatory for businesses with turnover above ₹5 Crore — auto-generated via the GSTN Invoice Registration Portal (IRP).