How do I calculate the total invoice value with GST?

Total invoice value = Base amount + GST amount. For intra-state supply, GST is split equally into CGST and SGST. For inter-state supply, the full GST is charged as IGST. For example, a base amount of Rs 10,000 at 18% GST gives a total invoice value of Rs 11,800.

What is the difference between CGST, SGST, and IGST on an invoice?

CGST (Central GST) and SGST (State GST) are charged equally on intra-state supplies (buyer and seller in the same state). IGST (Integrated GST) is charged on inter-state supplies (buyer and seller in different states). The total GST rate remains the same in both cases.

What GST rates apply to restaurant invoices?

Non-AC restaurants without ITC charge 5% GST. AC restaurants and those opting for ITC charge 18% GST. Outdoor catering services attract 18% GST with ITC. Cloud kitchens and food delivery are taxed at 5% without ITC.

Is GST calculated on the base amount or MRP?

GST is calculated on the taxable value (base amount), not the MRP. The taxable value is the price after deducting any trade discounts but before adding GST. For services, it is the service fee before tax.

How do I add discount to a GST invoice?

Discounts given before or at the time of supply reduce the taxable value. GST is then calculated on the reduced amount. Post-supply discounts must be linked to the original invoice and require a credit note. This calculator applies discounts before computing GST.

What is the mandatory information required on a GST invoice?

A GST invoice must include: supplier's name, address, and GSTIN; invoice number and date; recipient details and GSTIN (if registered); HSN/SAC code; description and quantity of goods/services; taxable value; GST rate and amount (CGST+SGST or IGST); total invoice value; and place of supply.

Can I claim ITC on the GST shown in the invoice?

Yes, registered businesses can claim Input Tax Credit (ITC) on GST paid on purchases if the invoice is valid, the supplier has filed returns, and the goods/services are used for business purposes. ITC cannot be claimed on blocked categories like food and beverages for personal consumption.

What is the time limit for issuing a GST invoice?

For goods, the invoice must be issued at or before the time of supply (delivery or payment, whichever is earlier). For services, the invoice must be issued within 30 days of providing the service. For banking and financial services, the limit is 45 days.

How is GST calculated for inter-state restaurant supplies?

Inter-state restaurant supplies (like catering at an event in another state) attract IGST at 18%. The full GST amount is charged as IGST instead of being split into CGST and SGST. The supplier must have GST registration in the state where supply occurs.

What happens if I issue a GST invoice with wrong tax amount?

If the tax charged is higher than required, a credit note must be issued. If the tax charged is lower, a debit note is required. Both must be reported in the GST return for the relevant period. Incorrect invoices can lead to ITC denial for the buyer and penalties for the supplier.

GST Invoice Value Calculator | Free Invoice Amount Calculator

What is GST Invoice Value?

GST invoice value is the total amount payable by the buyer, including the taxable value of goods or services plus the applicable GST. Every registered business in India must issue a GST-compliant invoice showing the tax breakup for each transaction. The invoice value determines how much the buyer pays and how much tax the seller collects and remits to the government.

Understanding GST invoice value is critical for accurate billing, filing GST returns, and maintaining compliance with the CGST Act 2017. Whether you run a restaurant, retail shop, or service business, every sale must be supported by a valid tax invoice.

GST invoice value = Taxable Value + CGST + SGST (intra-state) or Taxable Value + IGST (inter-state)
Four GST slabs apply: 5%, 12%, 18%, and 28% depending on the goods or service category
Discounts given at the time of supply reduce the taxable value before GST calculation
The invoice must include GSTIN, HSN/SAC code, tax breakup, and place of supply

How to Calculate GST Invoice Value

Calculating the total invoice value requires knowing the base amount, applicable GST rate, and whether the supply is intra-state or inter-state. You can use the GST Calculator for a quick GST amount lookup, or this tool for the complete invoice breakup.

Invoice Value = (Base Amount - Discount) + GST Amount

Step 1: Start with the base amount (price of goods/services before tax)

Step 2: Deduct any trade discount to get the taxable value

Step 3: Apply the GST rate to the taxable value

Step 4: For intra-state, split GST equally into CGST and SGST. For inter-state, charge full amount as IGST

Step 5: Add GST to taxable value to get total invoice value

GST Invoice Calculation Example

Here is a worked example for a restaurant issuing an intra-state invoice:

Base Amount: ₹10,000

Discount: ₹500

Taxable Value: ₹10,000 - ₹500 = ₹9,500

GST Rate: 5% (non-AC restaurant)

GST Amount: ₹9,500 x 5% = ₹475

CGST (2.5%): ₹237.50

SGST (2.5%): ₹237.50

Total Invoice Value: ₹9,500 + ₹475 = ₹9,975

If this were an inter-state supply (catering in another state), the full ₹475 would be charged as IGST instead of splitting into CGST and SGST.

GST Rates for Common Business Categories

Different goods and services attract different GST rates. Here are the rates relevant to restaurant and business invoicing as per CBIC notifications:

Category	GST Rate	ITC Available	Invoice Type
Non-AC Restaurant (dine-in)	5%	No	Tax Invoice
AC Restaurant / Star Hotels	18%	Yes	Tax Invoice
Outdoor Catering	18%	Yes	Tax Invoice
Cloud Kitchen / Food Delivery	5%	No	Tax Invoice
Packaged Food Products	5-18%	Yes	Tax Invoice
Software / IT Services	18%	Yes	Tax Invoice

How to Use This GST Invoice Calculator

Generate accurate GST invoice values in seconds with this free tool:

Step 1: Enter the base amount (taxable value of goods or services before GST)
Step 2: Select the applicable GST rate (5%, 12%, 18%, or 28%) based on your product or service
Step 3: Choose supply type: Intra-State for same-state transactions (CGST + SGST) or Inter-State for cross-state (IGST)
Step 4: Optionally enter any trade discount to be deducted before GST calculation
Step 5: Click "Calculate Invoice Value" to see the total amount with complete tax breakup

Mandatory Fields in a GST Tax Invoice

Section 31 of the CGST Act 2017 requires every GST-registered business to issue a tax invoice for supply of goods or services. The GST compliance requirements mandate the following fields:

Invoice number: Unique, sequential, and not exceeding 16 characters. Can contain alphabets, numerals, and special characters (/ and -)
Date of issue: Must be the date of supply or earlier
Supplier details: Name, address, and GSTIN of the seller
Recipient details: Name, address, and GSTIN (if registered) of the buyer
HSN/SAC code: Harmonised System of Nomenclature code for goods or Services Accounting Code for services
Tax breakup: Taxable value, CGST, SGST, or IGST amount with rate percentages
Place of supply: Determines whether CGST+SGST or IGST applies

Credit Notes and Debit Notes in GST Invoicing

When the original invoice needs adjustment, GST law provides for credit notes (reducing the invoice) and debit notes (increasing the invoice). Understanding these is essential for accurate return filing:

Credit note: Issued when goods are returned, excess tax is charged, or post-supply discount is given. Reduces the tax liability of the supplier
Debit note: Issued when the original invoice understates the taxable value or tax rate. Increases the invoice value
Time limit: Credit notes must be issued before the earlier of: September 30 of the following financial year, or the date of filing the annual return
Reporting: Both credit and debit notes must be reported in GSTR-1 and reflected in the recipient's GSTR-2A/2B

GST Invoice Value Calculator