VAT declaration is an important step in corporate financial management, ensuring compliance with the law and avoiding administrative penalties. In 2025, many businesses still make mistakes such as declaring incorrect tax rates, omitting input invoices or recording incorrect tax amounts. For example, a training company in the first quarter of 2025 had revenue of VND 2.4 billion but incorrectly declared input invoices of VND 50 million, leading to a difference in the amount of tax payable. Understanding common errors and how to fix them will help you declare VAT accurately, save time and limit risks.
See more articles at: VAT Overview – MAN
Overview of VAT declaration
What is VAT?
VAT is an indirect tax, applied to the added value of goods and services during the production, circulation and consumption process. VAT is calculated based on the difference between the output and input value of products and services. This is an important source of revenue for the state budget, helping to regulate the economy, make the market transparent and limit tax losses in all stages of the value chain.
See more articles at: What is VAT? Subjects subject to VAT in 2025
What is VAT declaration?
VAT declaration is the process by which a business or business household prepares a periodic tax declaration, reporting the output VAT and input VAT deducted. The goal is to determine tax obligations to the tax authority, ensure that the business complies with the law, and protect the right to a tax refund when eligible. Declarations can be made monthly or quarterly, depending on the scale and method of tax calculation.
See more articles at: VAT declaration and payment
Common errors when declaring VAT and their causes
In the process of declaring VAT, businesses often encounter many common errors. These errors not only affect the amount of tax payable but also affect the deduction and refund rights and the reputation of the business with the tax authority. For easy monitoring and management, the table below summarizes common errors when declaring VAT, the causes and consequences. This table helps businesses clearly understand the problem, thereby proactively preventing and promptly correcting them.
| STT | COMMON ERRORS | REASON | CONSEQUENCE |
| 1 | Invoice with wrong tax rate | Staff do not clearly understand tax rates of goods/services; lack of inspection process; not updated with new documents | Tax payable errors; may be subject to additional collection, administrative fines; affect reputation |
| 2 | Missing input/output invoices | Manual invoice management; lack of periodic reconciliation; not using synchronous accounting software; lack of human resources checking | Reduction of deduction rights or understatement of tax payable; required to file supplementary return; subject to penalty |
| 3 | Duplicate invoice declaration | Incomplete storage; unclear assignment of work; failure to check data before submission | Tax authority requests adjustment; additional tax payment; fined; reputation affected |
| 4 | VAT refund file error | Lack of understanding of procedures; no inspection checklist; no updated regulations; invalid invoices/documents | Tax refunds take longer to process; refunds are delayed; applications may be rejected; working capital affected |
| 5 | Late or non-submission of return | Lack of reminder system; accountants do not manage submission schedule; unclear assignment of responsibilities | Being fined for late payment; incurring penalty interest; reducing business reputation; affecting tax settlement |
| 6 | Error when using electronic declaration software | Staff not proficient in software; not updated to new version; lack of data checking process | Returned declaration; must be re-filed; late tax payment; impact on tax administration and reputation |
How to fix and prevent errors when declaring VAT
Invoice with incorrect VAT rate
Invoices with incorrect tax rates are a common mistake when declaring VAT, especially between levels 0%, 5%, 8% and 10% for specific goods and services such as education, healthcare or export. This error causes the declared output VAT amount to not match reality, leading to additional collection, administrative fines and affecting the reputation of the business during the periodic VAT declaration process.
- Fix: Review issued invoices, adjust tax rates according to regulations; prepare adjustment declarations and send them to tax authorities; use electronic invoice software with the function of automatically applying tax rates according to product groups.
- Prevention: Before issuing invoices, carefully check the tax rate; apply electronic invoice software; create a checklist when declaring VAT. In addition, regularly training accounting staff on tax rate changes and new regulations will help minimize errors.
See more articles at: VAT tax rates and corresponding taxable subjects in 2025 – VN Tax
Missing input or output invoices
Omitting invoices is a common mistake when declaring VAT. Omitted input invoices reduce deductible tax, omitted output invoices reduce payable tax, leading to under- or over-declaration. This mistake often occurs when businesses do not use synchronous management software or accountants do not periodically reconcile. In addition, omitting invoices also causes difficulties when refunding taxes, because missing documents will be returned by the tax authority, slowing down the business's cash flow.
- Fix: Periodically compare invoices with accounting books; prepare additional declarations to adjust data, ensure deduction rights and correct tax payment obligations.
- Prevention: Use invoice management software to synchronize with the declaration; check data periodically; assign personnel to compare input and output invoices. When making a VAT declaration, you should summarize all invoices in the period to avoid omissions.
See more articles at: What are Output VAT and Input VAT? New updates in 2025 – VN Tax
Duplicate invoice declaration
Some businesses make the mistake of declaring the same invoice multiple times during the VAT declaration process, especially when invoice management is manual or the staffing is unclear. This error leads to increased output tax or incorrect input tax deduction. When discovered by the tax authority, the business will have to prepare an adjusted declaration, pay additional incorrect tax and may be fined. Errors in declaring duplicate invoices waste time, increase personnel costs and complicate the tax control process.
- Fix: Identify duplicate invoices, cancel redundant declarations; prepare adjusted declarations; check data before submission.
- Prevention: Store all invoices; check data before making declarations; assign responsibilities clearly. Applying software that automatically checks for duplicate invoices will significantly reduce this error when declaring VAT.
See more articles at: VAT Invoice – MAN
VAT refund file error
VAT refund dossiers that lack documents, contain inaccurate information or do not comply with the prescribed form are also common errors when declaring VAT. This error causes the tax authority to return the dossier, prolonging the time to receive the tax refund and affecting the working capital of the enterprise. The main reason is that the accountant does not fully understand the latest tax refund dossier regulations or does not have a checklist to check.
- Fix: Supplement missing documents; check information is complete and correct; submit tax refund application according to tax authority instructions.
- Prevention: Create a tax refund checklist; ensure bank payments and valid invoices; develop a standard process for checking documents before sending. Training accountants on the latest tax refund documents will minimize errors.
See more articles at: VAT Refund – MAN
Late or non-submission of periodic returns
Error: Late submission or omission of a declaration period when filing VAT returns is a common mistake, especially among small and medium-sized enterprises. This leads to late payment penalties, interest penalties as prescribed, and affects the reputation of the tax authorities. The cause is often due to the lack of a reminder system, ineffective management of the declaration submission schedule, or the accountant not closely monitoring the declaration period.
Fix: Submit late declaration with penalty amount if any; make a self-inspection record and explain to tax authorities.
Prevention: Set up a system to remind about the deadline for declaration; clearly assign responsibilities to responsible personnel; schedule regularly to control all VAT declaration periods.
See more articles at: Deadline for VAT declaration and deduction in 2025: What should businesses pay attention to?
Error when using electronic declaration software
Error: When filing VAT returns online, businesses may make mistakes in entering incorrect data, submitting incorrect forms, or using outdated software. As a result, forms are returned, have to be re-filed multiple times, and slow down the process of filing and paying taxes. The reason is that staff are not proficient in the software or have not checked the data before submitting.
Fix: Check data, resubmit declaration in correct format; update new software; train staff to use it proficiently.
Prevention: Train staff to use electronic declaration software; test data before submission; regularly update new versions to avoid technical errors; apply internal inspection procedures before official VAT declaration.
Summary table of ways to fix and avoid errors when declaring VAT
To help businesses easily identify common errors when declaring VAT and know how to handle them effectively, the table below summarizes each error in detail, how to fix it as well as preventive measures. Applying these instructions not only helps ensure accurate declaration data, reduce risks with tax authorities, but also optimizes the invoice management process, improving the efficiency of accounting and financial work of the business.
| STT | COMMON ERRORS | HOW TO FIX | PREVENTION |
| 1 | Invoice with wrong tax rate | Review issued invoices, adjust correct tax rates; prepare adjustment declarations; use software to automatically apply tax rates | Check tax rates before issuing invoices; use electronic invoice software; build a checklist |
| 2 | Missing input/output invoices | Check invoices and books periodically; make additional declarations to adjust data. | Apply synchronous invoice management software; check periodically; assign personnel to compare data |
| 3 | Duplicate invoice declaration | Identify duplicate invoices, cancel excess declarations; prepare adjustment declarations | Store invoices fully; check data before submitting; clearly assign responsibilities |
| 4 | VAT refund file error | Supplement missing documents; check information is correct; submit application according to instructions | Prepare tax refund checklist; ensure payment via bank; use valid invoices |
| 5 | Late or non-submission of periodic returns | Submit late declaration with fine amount if any; make a self-inspection record and explain | Set up a system to remind about declaration deadlines; assign specific responsibilities |
| 6 | Error when using electronic declaration software | Check data, resubmit declaration in correct format; update software; train staff | Train staff to be proficient in the software; test declarations before submission; update new versions |
Some practical situations and lessons learned related to VAT declaration
Situation 1: Seafood exporting enterprises suffer from capital stagnation due to slow tax refunds.
In export activities, businesses often face many risks related to VAT, especially when making tax refunds. VAT declaration not only directly affects working capital but also impacts the ability to expand production and maintain the supply chain. The following situation illustrates a practical example from Can Tho Seafood Company, when a seafood exporting company encountered difficulties due to delayed tax refunds, leading to frozen capital and extended tax refund periods, thereby affecting business plans and cost management.
| CONTENT | DETAIL |
| Background | Can Tho Seafood Company specializes in exporting pangasius to European, American and some East Asian markets. In the first quarter of 2025, export revenue reached VND 200 billion, of which input VAT excluding deduction was VND 25 billion. The company mainly imports raw materials, processing supplies and packaging from domestic and foreign suppliers. |
| Problem | According to the 2008 VAT Law, VAT declaration requires complete documentation and documents to be closely checked. Many documents are required to be supplemented or corrected, leading to a tax refund period of 6-9 months. Working capital is frozen, affecting the purchase of raw materials and production expansion. |
| Consequence | The delay in tax refunds and errors in VAT declarations caused the company to have about 20-25 billion VND in capital stagnation, affecting the supply chain with pangasius farmers. Some export orders were delayed, reducing the company's revenue and reputation. |
| Lesson | The 2024 VAT Law improves processes: applying electronic invoices, transparent documents, connecting customs data and the “refund first, check later” mechanism for businesses with less risk. The tax refund time is reduced to 1-2 months, cash flow is rotated faster, helping companies invest in processing, expand exports and improve competitiveness. Standardizing documents and applying electronic invoices helps optimize cash flow and accurately declare VAT. |
Scenario 2: Individuals using private healthcare services
In modern life, the use of private medical services is increasingly popular, especially for people with average and high incomes. However, the cost of these services often includes VAT, which directly affects personal spending budgets. To illustrate the impact of VAT before and after the application of the VAT Law 2024, we present a specific situation of an individual going for a periodic health check-up at a private hospital, thereby helping readers understand how to declare VAT and the new tax exemption incentives.
| CONTENT | DETAIL |
| Background | Mr. Minh, an office worker in Ho Chi Minh City, earns about 12 million VND/month. He usually has a regular health check-up at a private hospital, each time costing 2 million VND, of which 5% is VAT (100,000 VND). He has check-ups 2-3 times a year, with a total tax cost of 200,000 - 300,000 VND. |
| Problem | Before the 2024 VAT Law, basic healthcare services were still subject to tax, increasing costs, especially for low- and middle-income earners. Incorrect VAT declarations or failure to update information made it difficult for people to take advantage of tax exemptions. |
| Consequence | People may limit regular check-ups to save costs, leading to the risk of late disease detection. VAT declaration becomes a financial barrier in the context of popular private healthcare services. |
| Lesson | The 2024 VAT Law exempts basic healthcare services from tax, helping to reduce costs for people. Mr. Minh and other low- and middle-income families save hundreds of thousands of VND each year, and are encouraged to have regular check-ups. This is a clear example of the impact of VAT declaration and the new law on living costs and public health. |
Situation 3: Restaurant business household incorrectly declares VAT
In the food service business, compliance with regulations on VAT declaration and payment plays a key role in avoiding legal and financial risks. However, many small businesses still have the habit of manual declaration and do not fully understand the new regulations of the VAT Law 2024, leading to unnecessary errors. To illustrate, the following situation shows a restaurant in Hanoi that got into trouble when it incorrectly declared taxable revenue, resulting in underpayment of tax and being fined.
| CONTENT | DETAIL |
| Background | Pho Viet restaurant in Hanoi, April 2025 revenue is 120 million VND, of which 10% is VAT payable (12 million VND). The restaurant owner self-declared on paper and did not fully understand the new regulations of the 2024 VAT Law on VAT declaration and tax rates applicable to each item. |
| Problem | The restaurant owner mistakenly declared taxable revenue of only VND100 million, resulting in a tax underpayment of VND2 million. The tax authority discovered this during a routine inspection and requested additional payment along with a fine. |
| Consequence | The restaurant was fined 5% on the amount of tax underpaid, equivalent to 100,000 VND, and had to pay an additional 2 million VND in tax arrears. This reduced profits and caused administrative pressure. The error stemmed from inaccurate VAT declaration. |
| Lesson | Need to update knowledge about VAT declaration, especially about revenue, tax rates and electronic invoice records. Using accounting software/electronic invoices helps to declare accurately, avoid errors and legal risks. Periodically check accounting data and invoices to ensure correct revenue and tax, minimizing administrative fines. |
Recommendations for businesses on VAT declaration
Based on real-life situations and common errors in VAT declaration, businesses need to proactively apply measures to ensure accurate declaration, optimize cash flow and avoid legal risks. Here are some practical recommendations:
| RECOMMENDATION | DETAIL |
| Update knowledge on VAT Law 2024 and VAT declaration | Businesses need to regularly update changes in the 2024 VAT Law to accurately declare VAT. Mastering knowledge helps accounting staff make correct VAT declarations, avoiding errors, being charged back or being fined. |
| Use accounting software and electronic invoices to declare VAT | Applying accounting software integrated with electronic invoices helps automatically check for duplicate invoices, apply the correct tax rate to the goods/services group and quickly summarize VAT declaration data. Helps save time and reduce the risk of errors when declaring VAT. |
| Standardize VAT declaration documents and procedures | Enterprises should develop a standard process for collecting, storing and comparing input and output invoices. Standardizing documents and applying a checklist before declaring VAT helps limit errors such as missing invoices, declaring duplicate invoices or late submission of declarations. |
| Check and compare VAT declaration data periodically | Periodically compare invoices, accounting books and VAT declaration data to detect and correct errors in a timely manner. This step helps businesses declare VAT correctly, avoid penalties and optimize cash flow. |
| Training staff and assigning clear responsibilities in VAT declaration | Enterprises need to regularly train their staff on new VAT declaration regulations, tax refund processing, and the use of accounting software and electronic invoices. Clearly assigning responsibilities helps ensure that periodic VAT declarations are not mistaken or omitted. |
| Set up a reminder system and manage VAT declaration deadlines | Schedule reminders for monthly or quarterly VAT declarations, track the progress of declaration submissions and the amount of tax payable. The reminder system helps limit late or missed VAT declarations, avoiding fines and late payment interest. |
| Optimize VAT refund process | Develop a standard process when preparing tax refund documents, ensuring all valid documents, payment via bank and VAT declaration in accordance with regulations. Helps reduce the risk of returned documents, shorten the time to receive tax refunds, and improve cash flow for production and business. |
Conclude
VAT declaration is a key factor in tax management of enterprises, affecting cash flow, profits and reputation with tax authorities. Errors such as issuing invoices with incorrect tax rates, omitting or declaring duplicate invoices, and errors in tax refund records can lead to fines, tax arrears and business interruption. The VAT Law 2024 improves regulations, supporting enterprises to declare more easily thanks to electronic invoices, transparent processes and quick tax refund mechanisms.
To ensure accurate VAT declaration, businesses need to regularly update their knowledge, use accounting software and electronic invoices, standardize records, periodically check data and clearly assign responsibilities. Applying these measures not only reduces legal risks but also optimizes cash flow and improves tax management efficiency.
Let MAN – Master Accountant Network accompany you in implementing the accurate VAT declaration process, optimizing records, quickly refunding taxes and minimizing risks. Contact MAN now for in-depth advice and comprehensive support on VAT declaration for your business.
Contact information:
MAN – Master Accountant Network
- Address: No. 19A, Street 43, Tan Thuan Ward, Ho Chi Minh City
- Hotline: 0903 963 163 – 0903 428 622
- E-mail: man@man.net.vn
