What are the regulations on input and output invoices?

From July 1st, 2026, regulations on electronic invoices and electronic documents will be implemented according to the new legal framework, including Decree 254/2026/ND-CP and Circular 91/2026/TT-BTC. Therefore, internal procedures developed from Decree 123/2020/ND-CP or Circular 78/2021/TT-BTC need to be reviewed before continued application.

For businesses, the important goal is not to make the value of input and output invoices "balance," but to ensure that each transaction has proper documentation, is recorded at the right time, and has verifiable data.

What are input invoices and output invoices?

Input invoice In accounting, this refers to the invoice that a business receives from a supplier when purchasing goods or services. This invoice is a component of the business's purchasing records, accounting, and tax eligibility assessment.

Output invoice An invoice is a document issued by the seller when a sale of goods or provision of services occurs that requires an invoice. For businesses selling goods, this is a document directly related to revenue, tax obligations, and transaction records with customers.

It's important to note that "input" and "output" describe the position of an invoice within a business's transaction flow. The same invoice can be an output for the seller but an input for the buyer.

For a detailed look at purchase documents, see What are input invoices and key control points?.

Why do businesses need to control both input and output invoices?

These two sets of invoices form part of the data trail from purchase to sale. Good management helps accountants not only prepare tax returns but also control accounts receivable, expenses, revenue, and transaction traceability.

• Input: It helps to reconcile suppliers, goods or services received, payment obligations, and purchase records.
• Output: It helps record sales transactions, track revenue, customer accounts receivable, and tax obligations.
• Two-way connection: This helps detect situations requiring verification, such as goods sold but purchase documents not yet received, inconsistent product names, or unusual discrepancies between inventory, purchase, and sales data.

Therefore, simply having an invoice is not the end point. Accountants must also be able to answer which transaction the invoice relates to, whether the goods or services were received/delivered, who approved it, and what documents prove the transaction.

Four layers of scrutiny are needed when applying regulations on input and output invoices.

Principles for issuing output invoices: prioritize accurate timing.

Businesses must determine when to issue invoices based on the nature of the transaction involving the sale of goods or provision of services, rather than waiting for payment or for complete internal documentation before issuing invoices.

When the sales process separates sales, inventory, operations, and accounting, businesses should clearly define which events trigger an invoicing request and who is responsible for transferring the data to accounting.

What should be checked on input invoices before accounting and payment?

Verification of input invoices should begin with the actual transaction, not just the invoice PDF file.

1. Identify suppliers and transactions: Does the invoice belong to the supplier with whom the business actually transacts?.
2. Compare the content: The name of the goods/services, quantity, value, and buyer information should be included in the order or contract.
3. Inspection and acceptance: Confirm that the business actually received the goods or services.
4. Check the invoice status: Please note that the invoice may be an adjustment, replacement, or have a change in status.
5. Considering tax conditions: Separate the verification of invoice existence from the conditions for VAT deduction.
6. Check payment: Determine whether the transaction falls under the category requiring non-cash payment documentation.

With a purchasing process that includes purchase orders (POs) and delivery receipts, comparing the PO → delivery/warehouse entry → invoice helps accountants detect discrepancies before recording liabilities or making payments.

How does the 5 million VND threshold affect input invoices?

For goods and services purchased worth 5 million VND or more, including VAT, businesses need to consider the conditions regarding non-cash payment documents to deduct input VAT, except in cases otherwise stipulated by law.

For deferred or installment purchases, the time when payment documents are required should be considered in conjunction with the payment terms in the contract. Therefore, the accounts receivable control system should track the due date as well, not just check the invoice status on the accounting date.

Is it possible to issue an output invoice without having received an input invoice?

The obligation to issue output invoices should not be delayed simply because the accountant has not yet received input invoices. Businesses need to determine their output obligations based on the sales transaction and the time of invoice issuance applicable to that transaction.

For example, a business has actually received the goods, has a contract and delivery documents, and then sells them to a customer, but the supplier is slow to send the invoice. In this case, two issues need to be separated:

• Does the business's sales transaction give rise to an invoice issuance obligation?;
• Does the supplier issue input invoices to the business on time?.

It is not advisable to process invoices that do not reflect actual transactions by purchasing or legitimizing them. Instead, records of purchases, deliveries, warehousing, and working with suppliers to process invoices correctly should be maintained.

This case has several exceptions depending on the type of transaction. See separate instructions for details. How to handle input invoices issued after output invoices..

Is it necessary to balance input and output invoices to make them equal?

There is no accounting principle that requires the value of input and output invoices for a given period to be equal. The two sets of invoices reflect different transactions and are also influenced by inventory, timing of purchase and sale, profit margins, production cycles, returns, and many other factors.

What accountants need to do is not "buy additional input invoices" to make the figures look better, but rather explain the discrepancies using inventory data, sales records, and the nature of the business operations.

6-Step Process for Controlling Input and Output Invoices

This also serves as a foundation for building invoice processing flow This allows for seamless control instead of each department holding a separate piece of data.

When does the manual invoice processing process start becoming a bottleneck?

Excel, email, and checking each invoice individually may still be suitable when the number of transactions is small. Problems arise when the accounting team has to check multiple data sources, multiple suppliers, or multiple branches within the same period.

Some signals that warrant reviewing the process include:

• Invoices arrive via various emails and channels;
• It's difficult to know which invoices have been checked or paid;
• Purchase orders (PO), delivery notes, and invoices are stored in separate systems;
• Accountants frequently discover duplicate or incorrect invoices after they have already been processed.;
• It takes a lot of time to retrieve documents during audits or settlements;
• It is difficult to determine who approved a transaction.

In this context, businesses can consider Bizzi's solution for processing input invoices. as a next step in assessing the suitability of the current process.

Frequently Asked Questions about Input and Output Invoices

Is it okay if the input invoices are higher than the output invoices?

It's impossible to draw conclusions solely from invoice values. The underlying causes need to be examined, such as inventory, asset purchases, buy-now-sell transactions, or seasonal fluctuations. The focus is on proving the transaction and providing relevant accounting data.

Is it unusual for invoices to exceed input invoices?

Not necessarily. Businesses can sell off leftover stock from the previous period or provide services with a low direct input cost. However, for businesses trading in goods, it is essential to ensure a reliable supply of goods and verifiable inventory data.

Payment in advance or invoice issued first?

There is no single order for all transactions. The timing of invoicing depends on the type of goods or services and the specific circumstances. Receiving payment in advance can affect the timing of invoicing for some services, so it's necessary to check the regulations applicable to the transaction.

Can the product names on input invoices be different from those on output invoices?

It's not advisable to judge solely by whether the names match character for character. Businesses need to demonstrate a link between purchased and sold goods, especially when there's processing, modification of specifications, packaging, or the use of different internal product codes.

Is it permissible to sell goods without receiving input invoices?

It's important to distinguish between not receiving an invoice and the absence of an actual purchase transaction. If goods have been purchased and received but the supplier is slow to issue an invoice, the business needs to maintain complete records of the purchase, delivery, and receipt of goods, and process the invoice with the supplier. The obligation to issue an output invoice still rests with the business's sales transaction.

Documents should be checked when building the invoicing process.

• Decree 254/2026/ND-CP on electronic invoices and electronic documents.
• Circular 91/2026/TT-BTC.
• Decree 144/2026/ND-CP amends regulations related to Value Added Tax (VAT)..

Because invoicing and tax regulations can be revised over time, businesses should check the effective date and revision text before using an outdated guideline as an internal procedure.