Proforma Invoice vs Tax Invoice: Difference Under GST

Did you know nearly 40% of invoices have errors? 

And most often, these errors start with how and when the invoices are used. For example, some invoices are used at the start of a sale, like a proforma invoice. Other invoices are used to confirm a sale, like a tax invoice.

If you have ever wondered which invoice to use and when, this blog is for you. Here’s a quick breakdown of a proforma invoice vs tax invoice in the context of GST, and when and how you should be using them in your business.

A proforma invoice is a preliminary document sent by a seller to a buyer, outlining the estimated costs and transaction details. It acts as a formal quotation, helping both parties agree on the terms. However, it is not a legally binding demand for payment.

Key characteristics

Generally, a proforma invoice:

• Is issued before shipment or service delivery
• Is used for quotation and buyer approval
• Is not recorded in accounting books
• Is not applicable to any tax liability

Where is it commonly used?

Proforma invoices are commonly used when clear information is needed before the actual transaction, such as in:

• Export business, where the buyer requires clear information before the deal.

• Situations where the seller requires pre-payment.

• Customs valuation, where it is used as a preliminary document.

A tax invoice is an official, legally valid document that records the transaction and specifies the amount payable along with applicable taxes, such as GST or VAT. Unlike a proforma invoice, this is the document that formalizes the sale and triggers both accounting and tax obligations.

Key characteristics 

A tax invoice is:

• Issued after the supply of goods and services
• Legally valid for accounting and audit purposes
• Used to break up the tax invoice in detail (GST/VAT components)
• A mandatory document for claiming Input Tax Credit (ITC)

Regulatory relevance

Tax invoices must comply with the rules set by tax authorities in each country. Some examples include:

• The Central Board of Indirect Taxes and Customs: India
• HM Revenue & Customs: UK
• The Internal Revenue Service: US

These authorities flag what is required in a tax invoice. For example, supplier information, GST/VAT, rates, and invoice numbering.

Here is a clear comparison of a tax invoice vs proforma invoice:

A proforma invoice can provide transparency in negotiations, as it includes all costs and details.

You'd normally use a proforma invoice:

• Before finalising an order, to enable the customer to obtain an accurate cost estimate.
• During export deals, where the customer requires a formal document to enable them to proceed.
• During customs procedures, as a preliminary guide for valuation.
• When calling for advance payment, particularly for large or export orders.
• To obtain internal approvals/enable the customer to obtain budget or procurement approvals.

The general process looks like this:

Exporter sends proforma invoice → Buyer reviews and approves → Advance payment is made → Goods are shipped

A tax invoice is relevant when a transaction is complete, i.e., when goods are delivered, or services are rendered. It is here that a sale is acknowledged, and tax liability is incurred.

A tax invoice is sent out to ensure GST/VAT compliance, proper accounting, and to facilitate Input Tax Credit for the buyer.

You’ll typically issue a tax invoice in the following situations:

• After goods are delivered, to formally record the completed supply
• After service completion, to prove that the service has been fully rendered
• When GST/VAT becomes applicable, triggering the tax liability
• For accounting and audit purposes, ensuring the transaction is properly recorded in the books

In export deals, it’s not only the proforma invoice vs tax invoice differences you should be familiar with, but also commercial invoices. 

To put it in simple words:

• A proforma invoice is a preliminary estimate.
• A commercial invoice is the final invoice used for customs.
• A tax invoice is the official document for accounting and tax compliance.

Understanding the difference in export transactions

In cross-border trade, the proforma invoice is used at the outset of the trade contract for the buyer’s discussion and approval. It is also used for making advance payments for goods.

Once the trade contract is approved and goods are ready for shipping, a commercial invoice is used. This document contains information on the value of the goods, product description, and other shipping details required for customs clearance.

The tax invoice is used for GST and accounting purposes to ensure that trade contracts are recorded and processed correctly for tax purposes.

In GST, the type of invoice you use can directly affect your taxes and cash flow. 

This is where most businesses go wrong. Using the wrong invoice can result in errors and risks.

What you need to know

1. ITC can only be claimed using a valid tax invoice - A proforma invoice does not qualify, since it does not represent a completed taxable transaction.

1. GST liability is triggered at the time of supply - Tax only becomes relevant upon delivery of goods or completion of services, that is, after a tax invoice is raised. 

1. Incorrect documentation can lead to penalties - Incorrect documentation using invoices or incorrect tax details may result in penalties.

If a tax invoice is not issued correctly:

• Buyers may not be able to claim ITC.
• Sellers may face GST reporting mismatches.
• Transactions may get flagged during audits.

According to ClearTax, ITC claims will only work if your tax invoices and GST reporting are accurate. If you get your invoices wrong, you might end up with blocked credits and extra scrutiny.

Here’s what it looks like in a real-life export scenario.

Let’s say you get a request from a foreign buyer for a product quote. Instead of directly sending a final invoice, you send a proforma invoice. This is a statement of the cost, quantity, and other details of the deal. Once the buyer approves it, they can send you an advance payment to confirm the deal.

After this, you would then ship them the goods. Now, at this stage, you would issue them a commercial invoice for customs clearance and also a tax invoice for official records and GST compliance purposes.

And finally, the deal is closed with the final payment.

Now, imagine this happening across multiple countries, with different currencies and timelines. That’s where Xflow steps in.

It helps you keep track of the entire invoicing journey while simplifying cross-border and multi-currency transactions without the usual back-and-forth.

Some of the most common invoicing slips include:

• Using a proforma invoice as a final invoice, which may cause confusion in accounting and payments.
• Charging GST on a proforma invoice, when in reality, GST liability is yet to be triggered.
• Claiming Input Tax Credit without a proper tax invoice, which may cause rejection during filing.
• Not converting a proforma invoice into a tax invoice, which may cause a transaction to be incomplete from a compliance perspective.
• Using incorrect or inconsistent invoice numbering, which may cause audit and reconciliation problems.

Proforma and tax invoices are checkpoints in your transaction flow.

You set the tone with one. You close the deal with the other.

Do it right, and everything flows - approvals, GST, ITC, payments. Do it wrong, and you might experience delays. Delays that, sometimes, you may not easily recover from.

That’s why having the right system in place matters.

With Xflow, you can go beyond just managing invoices. From creating clean, payment-enabled invoices to receiving global payments seamlessly, Xflow is built to support your entire transaction lifecycle.

Ready to simplify your invoicing and global payments? Explore Xflow’s pricing and get started today.