Invoice + GST Breakdown Calculator

Calculate item-wise GST — CGST/SGST for intra-state, IGST for inter-state with invoice preview

Last updated: Jul 22, 2026 | Reviewed by Calkulator Team | 2 min read

Tax

Generate a quick GST invoice breakdown for any order

Add multiple line items with different GST rates and quantities to see the complete invoice — subtotal, item-wise tax, CGST/SGST or IGST split, and grand total. Useful for freelancers and small businesses preparing quotes.

Ensure HSN/SAC codes match the correct GST rate — wrong codes can lead to demand notices during audits.

Invoice Items

Item Name

HSN Code

Qty

Unit Price (?)

Discount %

GST Rate

Supply Type

Tax Computation

Taxable Value = Qty — Price — (1 - Discount%/100)

Intra-state: CGST = SGST = Taxable — Rate/2/100

Inter-state: IGST = Taxable — Rate/100

Grand Total

—

Incl. all taxes

Total Tax

—

CGST + SGST / IGST

Sub-total

—

Before discount

Total Discount

—

All items

Total Taxable Value

—

After discount

CGST Total

—

Intra-state only

SGST Total

—

Intra-state only

IGST Total

—

Inter-state only

Item-wise Breakdown

Item	HSN	Taxable	CGST	SGST	IGST	Total

TAX INVOICE

Generated by Calkulator

Date:

#	Item	Qty	Rate	Taxable	Tax	Amount

Live Result Illustration

Visual summary — updates instantly as you enter values above

LIVE

Real-Life Guide to Using the Invoice + GST

GST-inclusive invoice amount. Use the examples and checks below to turn the number into a practical decision.

When this calculator is useful

Freelancers, consultants, and small shop owners use this when they need to add GST to a quoted price before printing an invoice, or when a client has given a "final" number and they need to back out the base value and tax component from it.

For most people, the best way to use the Invoice + GST is to try the real case first, then change one input at a time. That makes the trade-off visible. For example, with a loan calculator you can change tenure while keeping the same rate; with an investment calculator you can change return assumption while keeping the same monthly contribution; with a health, education or measurement calculator you can check how much one input changes the final category.

The result should answer a practical question: Can I afford this? How much should I save? Is this score enough? Is this measurement within range? What is the safer or cheaper option? If the output does not answer the decision clearly, adjust the inputs until the scenario matches your real situation.

Real-Life Example

Freelancer billing an out-of-state client: A graphic designer based in Mumbai completes a ₹50,000 logo project for a client registered in Delhi, so the sale is inter-state.

1Base value ₹50,000 at 18% IGST = ₹9,000 tax, making the invoice total ₹59,000 with a single IGST line rather than a CGST/SGST split.

2Now change one input, such as rate, time, quantity, unit or score, and compare the new result with the first one.

Whether you split GST into CGST+SGST or charge a single IGST depends entirely on the supplier's and buyer's states, not on the amount.

Practical Advice

Use the Invoice + GST as a planning tool, not just a number generator. Write down the inputs you used, because the final answer is meaningful only when you remember the assumptions behind it.

If the decision affects money, health, tax, safety, academics or legal compliance, keep a second check ready. That second check may be a bank quote, payslip, official rule, prescription, site measurement, mark sheet or invoice.

Common Mistakes

Charging 18% GST on every sale by default, when many goods and services actually fall under the 5% or 12% slabs and a handful are exempt entirely.
Applying CGST + SGST (say 9% + 9%) on an inter-state sale instead of a single IGST line, which makes the invoice non-compliant even if the total tax amount is correct.
Treating a GST-inclusive price the client quoted as the base value and adding tax again on top, effectively overcharging the client by the tax amount a second time.
Backing out the base price from an inclusive amount by subtracting the percentage directly (e.g. ₹59,000 minus 18% = ₹48,380) instead of dividing by 1.18, which gives a wrong base of ₹50,000.
Rounding each line item separately on a multi-item invoice instead of rounding only the final total, causing the printed total to mismatch the sum of GST-wise breakups by a rupee or two.

How to Interpret Results

The output splits your entered amount into the taxable value and the GST amount (either as CGST+SGST for intra-state or IGST for inter-state); use the taxable value as the line-item price on your invoice and the tax figure as the separate GST column, not folded into the price.

A good interpretation looks at both the main result and the supporting values. If a page shows totals, ratios, categories, schedules or warnings, read those together instead of focusing only on the biggest number.

Invoice + GST FAQs

Useful answers for interpreting the output, avoiding mistakes and using the result responsibly.

What exactly does this calculator do?

It converts between a GST-exclusive base price and a GST-inclusive final price for a rate you choose (5%, 12%, 18%, or 28%), and shows the tax amount separately so you can place it correctly on an invoice.

How do I know whether to charge CGST+SGST or IGST?

If the supplier and the place of supply are in the same state, you charge CGST and SGST at half the rate each; if the buyer is in a different state, you charge the full rate as IGST instead. This depends on the buyer's registered address, not on the invoice amount.

My client says ₹59,000 is the "final, all-inclusive" price. How do I find the base amount?

Divide the inclusive price by (1 + GST rate as a decimal). At 18%, that is ₹59,000 ÷ 1.18 = ₹50,000 base, with ₹9,000 as the GST component — not a straight 18% subtraction from ₹59,000.

Which GST rate applies to my product or service?

Rates vary by HSN/SAC code and are not one-size-fits-all — most professional services fall under 18%, but many goods sit at 5% or 12%, and some categories are exempt. Check your specific HSN/SAC classification rather than assuming a default rate.

Do I even need to charge GST if I am a small freelancer?

GST registration and invoicing generally become mandatory once your turnover crosses the applicable threshold for your state and category of supply, with a lower threshold for services than for goods under the currently applicable rule. Below that, many small suppliers operate without GST registration.

Why does my printed invoice total differ from this calculator by a rupee?

That is usually a rounding difference — accounting software often rounds each line item to the nearest rupee before summing, while this calculator computes on the exact decimal amount you entered.

I issued an invoice with the wrong GST rate — what now?

You typically need to issue a credit note or debit note referencing the original invoice to correct the tax amount, rather than editing or reprinting the original invoice.

Can I use this for calculating GST on an advance payment or partial invoice?

Yes, enter the advance or partial amount as the base value — the same rate logic applies, but remember GST liability on advances can arise at the time of receipt for certain categories, so check the timing rule for your type of supply.

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.

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.

How 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.

Frequently 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).

descriptionInvoice + GST Breakdown Calculator