How to write an invoice to reduce, increase VAT, revenue, and tax?

How to write a reduced adjustment invoice This is something that many people in the accounting field are interested in. In the following article,Vindoo has summarized for readers how to create a reduced adjustment invoice along with an explanation of why this should be done. Follow along with us!

1. When to adjust the increase, decrease the invoice?

According to the provisions of Article 20 of Circular 39/2014/TT-BTC, invoices need to be adjusted up (down) when the buyer/seller realizes an error after completing the transaction and declaring tax. At this time, the wrong invoice is required to be adjusted up/down in accordance with the original book value.

Here are some specific situations where an invoice needs to be reduced:

  • The error was discovered after the invoice was sent to the buyer and tax was filed.
  • In case the goods reach the buyer with poor quality, defective and the seller accepts to reduce the selling price of the goods.
  • Adjustment to decrease when revenue decreases in construction and installation works.
  • Adjust the invoice reduction when the business is entitled to a commercial discount.

In the invoice for adjustment of increase/decrease, information such as: quantity of goods increased/decreased, VAT, selling price, etc. Based on these contents, the seller/buyer can adjust tax, input or output of the business.

In case the buyer's name has an error but the tax code is still correct, there is no need to issue an adjusted invoice.

Here are some notes that business accountants need to pay attention to when adjusting invoices:

  • Only correct information that is incorrect.
  • Negative numbers are not allowed in the adjusted invoice.
  • In the expense adjustment invoice, write the difference that needs to be corrected.
  • Seller and buyer need to have a written agreement stating the reason for modifying the invoice.

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2. Regulations on how to write reduced adjustment invoices

Regulations on decreasing invoices are clearly stated in Point e, Article 7 of Circular 78/2021/TT-BTC: Invoices with errors need to be adjusted up (marked with +) / decreased (marked with -) in accordance with the actual adjustment.

Also in Article 6 of this circular, enterprises or business individuals applying e-invoices shall make a written agreement between related parties when there is an error in the recording process. At the same time, this error should also be reported to the tax office and a new electronic invoice should be issued to replace the faulty one.

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3. How to write an adjustment invoice with errors that do NOT affect the amount

For example: On March 5, 2023, accounting company A discovered that a sales invoice declared from December 12, 2023, symbol AZ/12D, number 20032130 was wrong with the tax code.

To handle this error, the company has made the following corrections:

  • First, the company made a written value-added adjustment record.
  • After that, the accounting department created an invoice to adjust: No. 2002302, symbol AZ/12D, date of creation March 5, 2023 as follows:
How to write an adjustment invoice
How to write a reduced adjustment invoice

Since the tax declaration does not affect the amount, the business does not need to declare, but only needs to save the invoice + the adjustment record. At the same time, incorrect invoices should also be saved for future explanation.

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4. How to write an adjusted invoice with errors that affect the amount

Example: On March 2, 2023, Binh Minh Company sold 50 sets of tables and chairs to An Binh Company. This order issued invoice number 0004005 with symbol 2GH/AB on the same day. The unit price without VAT is 3 million VND/set. This transaction was declared in red in March 2023.

However, on April 12, 2023, An Binh company discovered an error in the invoice. Specifically, the price of a set of tables and chairs without tax is 2 million, but it is recorded as 3 million. Therefore, Binh Minh company has to issue an invoice to reduce the order for 50 sets of tables and chairs with 1 million VND/set.

To handle this problem, Binh Minh company needs to take two steps:

  • First, you need to make an invoice adjustment record.
  • Proceed to issue invoice number 0004009, symbol 2GH/AB, dated 12/04/2023, specifically:
How to write an adjusted invoice with errors that affect the amount
write an adjusted invoice with errors

5. How to write an invoice to reduce VAT and revenue

Example: The value added tax of item X is 10% but it is written as 15% in the invoice. This shows that the invoice is 5% skewed, VAT must be adjusted. This invoice was declared on 15/02/2023. On April 24, 2023, the company discovered the error and made a reduction as follows:

How to write an invoice to reduce VAT and revenue

6. How to write an invoice to increase VAT and revenue

Example: On 04/04/2023, company B discovered that invoice 009008 issued on 03/03/2023 was incorrectly declared VAT. The correct VAT of the item is 10%, but declared in the invoice is 5%. This shows that there is a 5% difference in reality and declaration. Since then, the accountant must make specific reduction adjustments as follows:

  • First, you need to make a record to process the invoice.
  • After that, the accountant needs to issue an adjusted invoice number 009008, symbol AB/3NP, dated 04/04/2023 specifically as follows:
How to write an invoice to increase VAT and revenue
write an invoice to increase VAT


Yes, you can adjust an invoice even after it has been paid. However, it’s important to communicate with the customer to let them know about the adjustment and any changes to the payment amount or terms.

Yes, it’s important to create a new invoice that accurately reflects the changes. Be sure to include a reference to the original invoice number and date.

Yes, there are many invoicing software programs available that can help automate the invoice adjustment process. However, it’s still important to review the adjustments carefully to ensure accuracy and completeness.

In the above post, Viindoo has compiled for readers the information related to How to write a reduced adjustment invoice?. Hopefully through this article, businesses have information to declare invoices accurately. Follow our next articles to learn more ways to invoicing quickly and accurately!

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Jun Nguyen April 28, 2023