Proforma Invoice vs Tax Invoice: What's Different

The short answer

Both documents look similar, but they do very different jobs. A proforma invoice is a preview of a sale that hasn't happened yet — a formal way of saying "here's exactly what it will cost and on what terms." A tax invoice is the real thing: proof that a sale took place and a record of the tax charged on it.

Think of the proforma as a firm quote dressed up like an invoice, and the tax invoice as the legal document that actually moves money and tax through your books. Mixing them up is one of the most common bookkeeping mistakes small businesses make, and it can cause problems at tax time for you and your customer.

What is a proforma invoice?

A proforma invoice is a preliminary bill you send before a sale is confirmed. It sets out the goods or services, quantities, unit prices, estimated taxes, and payment or delivery terms — so the buyer knows precisely what to expect. It is issued in good faith, but it is not a demand for payment and it does not create an accounting entry.

Because it isn't a legal record of a sale, a proforma should never be entered as revenue, and neither party can use it to claim or report tax. It is a planning and agreement tool, not a financial one.

• Clearly labelled "Proforma Invoice" so it can't be mistaken for the real bill
• Shows estimated amounts that may still change before the final invoice
• Commonly used for quotes, deposits, customs pre-clearance, and getting internal purchase approvals
• Has no bearing on your tax return and is not recorded as income

What is a tax invoice?

A tax invoice is the official document you issue once a sale is agreed or goods and services are supplied. It is the record both you and your buyer rely on: you use it to report the tax you collected, and your buyer uses it to claim back any tax they're entitled to and to record the expense.

Most tax systems require a tax invoice to contain specific details, and issuing one usually creates a legal obligation — the amount becomes due and the tax becomes reportable. This is general information; the exact fields, naming and thresholds vary by country, so confirm current rules with your local tax authority or a qualified local tax professional before finalising your template.

• A unique, sequential invoice number and the issue date
• Your business name, address and tax registration number (where you're registered)
• The buyer's details, especially for business-to-business sales
• A clear description, quantities, unit prices and the total amount due
• The tax rate and tax amount shown separately from the net amount
• Payment terms and due date

Side-by-side: the key differences

• Purpose: a proforma proposes a sale; a tax invoice records a completed one
• Timing: proforma comes before agreement, tax invoice comes at or after supply
• Payment: a proforma is not a payment demand; a tax invoice makes the amount due
• Accounting: a proforma is never booked; a tax invoice is booked as revenue
• Tax: you cannot report or reclaim tax from a proforma — only from a valid tax invoice
• Editability: proforma figures can still change; a tax invoice should be corrected only with a credit note or a properly issued replacement

Worked example: a furniture order

Say a customer wants 10 office chairs. You send a proforma invoice listing 10 chairs at their unit price, estimated tax, delivery cost and payment terms, so they can get sign-off from their manager. Nothing is recorded in your accounts yet, and no tax is owed.

The customer approves and pays a deposit. When you deliver the chairs (or complete the agreed supply), you issue a tax invoice for the final amount, with the tax shown separately and a unique invoice number. That tax invoice is now the document that goes into your books, appears on your tax return, and lets the customer claim their input tax where eligible.

When to use each — a quick rule of thumb

1. 1

   Confirming a price or scope

   Send a proforma invoice so the buyer can approve exact quantities, prices and terms before you commit.

2. 2

   Requesting a deposit or pre-payment

   Use a proforma to set out what's expected, then issue a tax invoice once the goods or services are supplied.

3. 3

   Shipping or customs

   A proforma is often used to declare the value of goods before a final sale; the tax invoice follows once the transaction is complete.

4. 4

   Recording the actual sale

   Always issue a tax invoice — this is the only document you book as income and report tax on.

5. 5

   Fixing a mistake

   Adjust a proforma freely before it becomes an invoice; once a tax invoice is issued, correct it with a credit note or a formal replacement, not by editing the original.

Keeping both straight without the paperwork headache

The risk with juggling two document types by hand is small but costly: a proforma accidentally counted as revenue, a tax invoice with a duplicated number, or tax fields that don't meet your country's requirements. Getting the sequence and the tax details right every time is where a proper system earns its keep.

Tallium is an all-in-one accounting, POS, inventory and e-commerce platform for small and medium businesses. You can send a proforma as an estimate, then convert it to a compliant tax invoice in one step — carrying over the line items so nothing is retyped, keeping invoice numbers sequential, and calculating tax with the terminology your country uses. Because invoicing, sales and your books are one system, an issued tax invoice flows straight into your accounts and reports, while proformas stay out of your revenue until they're converted.

Tallium is priced per unit in USD, billed monthly from signup, cancel anytime, with no free trial: the shop/store plan is $79/month, online store $159/month, warehouse $99/month, and factory $269/month. Every plan includes the full core — accounting, tax handling, expense and receipt scanning, reports, the mobile app, AI insights and email support at support@tallium.online.