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✓ Updated April 2026  ·  Free  ·  No Signup

Invoice Calculator with GST & VAT

Add multiple line items, select your tax rate, and get instant subtotal, CGST/SGST breakdown, and grand total. Works for Indian GST invoices, UK VAT, EU VAT, and US sales tax.

Quick answer

Invoice tax = sum of (line amount × rate) for each taxable line

Enter items, quantities, and prices. Choose GST, VAT, or sales tax rate. The calculator shows subtotal, tax, and grand total — suitable for India GST invoices, UK VAT quotes, and US estimates.

India GST
CGST+SGST or IGST split
UK VAT
Typically 20% standard
Multi-line
One rate per invoice (group by rate if mixed)

1. Choose Tax Rate

2. Add Invoice Items

How to Use This Invoice Calculator

This free online invoice calculator is designed for anyone who needs to compute invoice totals with GST or VAT quickly and accurately. It works for Indian GST invoices, UK VAT, EU VAT, US sales tax, and any other percentage-based tax system. Here is how to use it in three steps:

  1. Select your tax rate — choose from the preset buttons (GST 5%, 12%, 18%, 28%, UK VAT 20%, Germany VAT 19%) or enter a custom rate. If you are doing an inter-state transaction in India, enable the IGST toggle to show the full integrated rate instead of splitting CGST and SGST.
  2. Add your invoice items — enter a description, quantity, and unit price for each product or service. Click "Add another item" to include as many line items as needed. The calculator supports unlimited items.
  3. Click "Calculate Invoice" — instantly see the subtotal, CGST/SGST breakdown (or IGST for inter-state), total tax amount, and grand total. Use the Copy button to copy the summary to your clipboard.

How GST is Calculated on an Invoice — With Examples

GST (Goods and Services Tax) is calculated as a percentage of the taxable value of goods or services. The formula is straightforward:

GST Amount = (Item Value × GST Rate) ÷ 100

Invoice Total = Item Value + GST Amount

Example 1: Single item at 18% GST

Item: Web Design Service₹10,000
CGST @ 9%₹900
SGST @ 9%₹900
Invoice Total₹11,800

Example 2: Three items at 12% GST

ItemNetTaxGross
Logo Design (×1 @ ₹5,000)₹5,000₹600₹5,600
Social Media Posts (×10 @ ₹200)₹2,000₹240₹2,240
Monthly Retainer (×1 @ ₹8,000)₹8,000₹960₹8,960
Total₹15,000₹1,800₹16,800

CGST = ₹900 (6%)  ·  SGST = ₹900 (6%)  ·  Total GST = ₹1,800 (12%)

GST Invoice Requirements in India

Under the GST Act, registered businesses are required to issue a tax invoice for every taxable supply. A valid GST invoice must contain the following mandatory fields:

·

Supplier Details

Name, address, and GSTIN of the seller

·

Invoice Number & Date

Consecutive, unique invoice number and date of issue

·

Buyer Details

Name, address, and GSTIN of recipient (for B2B)

·

Place of Supply

State name and code — determines CGST/SGST vs IGST

·

HSN/SAC Code

Harmonized code for goods (HSN) or services (SAC)

·

Taxable Value

The price before applying GST

·

GST Rate & Amount

Rate applied and CGST, SGST or IGST amounts separately

·

Invoice Total

Total amount payable including all taxes

CGST vs SGST vs IGST — Which Applies to Your Invoice?

The type of GST shown on your invoice depends on whether the transaction is intra-state (within the same state) or inter-state (across different states):

Intra-state supply

CGST + SGST

Seller and buyer are in the same state. GST is split equally — half goes to Centre, half to State.

18% GST = 9% CGST + 9% SGST
Inter-state supply

IGST

Seller and buyer are in different states. Full GST collected by Centre, then distributed to destination state.

18% GST = 18% IGST
Union Territory supply

UTGST

Applies in Union Territories like Delhi, Chandigarh, Lakshadweep instead of SGST.

18% GST = 9% CGST + 9% UTGST

Quick rule: If your client's billing address is in the same state as yours — use CGST + SGST. If they're in a different state — use IGST. Use the toggle in the calculator above to switch between the two.

Who Uses This Invoice Calculator?

💻

Freelancers

Calculate client invoices with 18% GST on services in seconds

🏢

Small Businesses

Generate accurate tax amounts for B2B invoices

🛒

eCommerce Sellers

Compute GST on product sales across India

📊

Accountants

Quick-verify invoice totals and tax breakdowns

🎨

Design Agencies

Bill clients for creative services with correct GST

🌍

UK/EU Businesses

Calculate VAT invoices for 20% UK or 19% EU rates

🏗️

Contractors

Add GST 12% or 18% to construction service invoices

📚

Educators

Check if educational services are GST exempt (0%) or taxable

How to use and formula

How to calculate tax on an invoice

For each line: line total = quantity × unit price. Tax = subtotal × rate ÷ 100.

  1. Add line items with description, quantity, and unit price.
  2. Select GST, VAT, or custom rate.
  3. Toggle IGST for inter-state India supply.
  4. Copy or download the breakdown for your invoice.
Formulas

Line total = quantity × price

Tax = subtotal × (rate ÷ 100)

Grand total = subtotal + tax

₹10,000 subtotal at 18% GST = ₹1,800 tax, ₹11,800 total.

Common mistakes to avoid

Mixing 5% and 18% lines without grouping

GST law expects rate-wise totals. Calculate separate subtotals when slabs differ.

Using IGST on intra-state B2B invoices

Same-state supply should show CGST and SGST, not IGST.

Forgetting tax-inclusive vs exclusive pricing

Confirm whether unit prices include tax before using add vs remove mode on other calculators.

Skipping mandatory invoice fields for compliance

GSTIN, HSN, place of supply, and invoice serial rules are not generated by this tool.

Official source and review note

Rates and rules on this page were last reviewed in May 2026 against CBIC / HMRC / IRS (by region). Use the linked authority for filing, registrations, or address-specific compliance.

Build compliant invoice totals

Use this calculator for quotes and draft invoices. Add GSTIN, HSN/SAC, and place-of-supply fields required by law before sending to clients.

India GST calculator →

Frequently Asked Questions — Invoice Calculator

How do I calculate GST on an invoice?+
To calculate GST on an invoice, multiply the item's taxable value by the GST rate and divide by 100. For example, an item worth ₹1,000 at 18% GST: GST = (1,000 × 18) ÷ 100 = ₹180. The invoice total is ₹1,000 + ₹180 = ₹1,180. For intra-state supply, ₹180 is split as ₹90 CGST + ₹90 SGST. Our calculator does this automatically — just enter the item value and select 18%.
What is the difference between CGST and SGST on an invoice?+
CGST (Central GST) and SGST (State GST) together make up the total GST on intra-state transactions. If the GST rate is 18%, CGST is 9% and SGST is 9% — each exactly half. CGST revenue goes to the Central Government and SGST goes to the State Government. For inter-state transactions, you charge IGST at the full rate instead. The toggle in our calculator lets you switch between CGST+SGST and IGST modes.
Can I use this calculator for UK VAT or EU VAT invoices?+
Yes, absolutely. This calculator works for any percentage-based tax system. For UK VAT at 20%, click "VAT 20% (UK)". For Germany at 19%, click "VAT 19% (DE)". For France TVA at 20%, use the 20% preset or enter a custom rate. The calculator shows net amount, tax amount, and gross total — which is all you need for a VAT invoice outside India. Note that for EU invoices, the column shows as "Tax" rather than CGST/SGST.
Is this invoice calculator accurate for Indian GST invoices?+
Yes, this calculator uses the official GST Council formula. GST Amount = (Taxable Value × Rate) ÷ 100, with CGST and SGST each being exactly half of the total GST. It is accurate for all standard GST rates: 0.25%, 3%, 5%, 12%, 18%, and 28%. The results match what you would see in GST-compliant billing software. For complex GST scenarios such as reverse charge, composition scheme, or imports, we recommend verifying with a chartered accountant.
What details should a valid GST invoice include?+
A valid GST invoice must include: your GSTIN, consecutive invoice number and date, buyer's name and GSTIN (for B2B transactions), description of goods or services with HSN/SAC code, quantity and value, GST rate applied, CGST and SGST amounts (or IGST for inter-state), and the final invoice total. For invoices above ₹50,000, the buyer's name and address are mandatory. This calculator helps you compute the tax amounts correctly so your invoice is GST-compliant.
How do I calculate invoice for multiple items with different GST rates?+
GST law in India requires that items with different tax rates be shown separately on an invoice. Our calculator currently applies one rate to all items (which covers the majority of use cases). If you have items at different rates — say some at 5% and others at 18% — the correct approach is to create separate calculations: one for 5% items and one for 18% items, then combine them manually. This is also the format required on a compliant GST invoice.

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50 states