Corporate income tax (CIT) declaration and payment is a mandatory part of every business's financial activities. In 2025, with changes from Circular 80/2021/TT-BTC, the process of preparing quarterly provisional declarations and year-end settlements is confusing many businesses. The following article will help you understand how to declare correctly, on time and in the right way - especially when the entire process is now done through the tax authority's electronic information portal.
Overview of corporate income tax declaration and payment obligations
For every business that generates taxable income in Vietnam, declaring and paying corporate income tax (CIT) is a mandatory and periodic financial obligation. This process includes two important periods: quarterly provisional declarations during the year and final CIT settlement at the end of the fiscal year.
According to the guidance in Circular 80/2021/TT-BTC, enterprises are allowed to choose to declare CIT monthly or quarterly, depending on the scale of revenue. However, in practice, quarterly declaration is still the more popular choice, especially for enterprises with total revenue in the previous year of less than 50 billion VND - the group that accounts for the majority of the structure of small and medium enterprises in Vietnam.
Do I have to submit a provisional corporate income tax return?
The answer is yes, but not all businesses understand this clearly.
Although according to Circular 80, enterprises are not required to pay provisional tax quarterly, they still have to prepare and submit provisional tax declarations. This helps tax authorities monitor financial situations and avoid large differences with the final tax amount at the end of the year.
Note: If the enterprise fails to submit the provisional declaration on time, it may be subject to administrative penalties according to the law. Decree 125/2020/ND-CP.
Quarterly corporate income tax declaration: Things businesses need to note
In practice, most small and medium-sized enterprises in Vietnam choose to declare corporate income tax (CIT) quarterly because it is suitable for their scale of operation and the regulations in Circular 80/2021/TT-BTC. This form of declaration helps businesses be more proactive in financial planning, while reducing the pressure of monthly declaration.
Below are the tax periods and deadlines for submitting quarterly provisional corporate income tax returns:
| Quarter | Tax period | Deadline for submission of declaration |
|---|---|---|
| Quarter I | 01/01 – 31/03 | 30/04 |
| Quarter II | 01/04 – 30/06 | 30/07 |
| Quarter III | 01/07 – 30/09 | 30/10 |
| Quarter IV | 10/01 – 12/31 | January 30th next year |
Business implementation declare according to Form 04/TNDN, in which provisional tax is determined according to the formula:
Provisional corporate income tax = Provisional taxable income × Current tax rate (20%)
Calculating taxable income correctly and promptly each quarter not only helps businesses avoid the risk of being charged back when finalizing, but is also an important basis for evaluating business performance at each stage. In case a business has large fluctuations in revenue and expenses, it is necessary to pay attention to adjusting the data to be closer to reality to ensure transparency with the tax authorities.
How to prepare corporate income tax finalization declaration according to Circular 80
The final settlement declaration uses form 03/TNDN issued with Circular 80. Enterprises must declare all income generated during the year, including:
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Taxable Revenue
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Deductible expenses under the Corporate Income Tax Law
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Carryover losses (if any)
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Applicable tax incentives (if applicable)
Reconciliation between the figures in the accounting books and on the declaration is mandatory to avoid discrepancies.
Note: Financial statements must be attached when submitting form 03/TNDN, including balance sheet, income statement, cash flow statement, etc.
Instructions for declaring form 04/TNDN according to TT80
Form 04/TNDN is a form issued by the Ministry of Finance with Circular 80/2021/TT-BTC, used to declare provisional corporate income tax quarterly. This is a concise form, does not require detailed declaration of each revenue - expense item, but still needs to ensure reasonable accounting basis and clear documentary basis.
The basic structure of form 04/TNDN includes 4 main indicators:
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Revenue during the period: Total revenue generated during the declared quarter, regardless of whether money has been collected or not.
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Expenses during the period: Including all reasonable and valid expenses according to the Law on Corporate Income Tax.
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Provisional profit: Is the difference between revenue and expenses after excluding non-deductible items.
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Quarterly tax payable: Determined by the formula: Provisional corporate income tax = Provisional profit × 20%
Although not as detailed as form 03/TNDN used for year-end settlement, form 04 is still the basis for tax authorities to closely monitor the business production activities of enterprises on a quarterly basis.
Currently, businesses can easily declare this form through the system. electronic taxThe portal has built-in forms, allowing businesses to download and fill them out manually or online, then digitally sign and submit them in just a few minutes.
Note: Although it is not mandatory to pay tax after making provisional declaration, enterprises must still submit form 04/TNDN on time to avoid being penalized for administrative violations.
Deadline for submitting provisional corporate income tax return and annual settlement
| Type of declaration | Deadline |
|---|---|
| Quarterly provisional (form 04) | Last day of the month following the declared quarter |
| Annual settlement (form 03) | 90 days from the end of the fiscal year (usually March 31 of the following year) |
Instructions for submitting corporate income tax returns via the electronic portal
The entire tax declaration and payment process has now been transferred to a digital platform at: Electronic tax
Steps to follow:
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Go to the e-tax website and log in with your business account.
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Select the function “Declare online” or “Submit tax return”.
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Select the appropriate form (03/TNDN or 04/TNDN), upload XML file or fill in directly.
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Sign with USB Token and send.
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Track receipt notifications and processing results.
Note: It is recommended to use IE or Chrome browser version that supports Java Plugin to avoid system errors.
Prestigious corporate income tax declaration and settlement service for businesses
Filing corporate income tax returns in the correct form, on time, and in accordance with the law not only helps businesses avoid fines but also optimize financial efficiency. If you are looking for a comprehensive solution, please refer to Auditing services at MAN.
MAN's team of experts will accompany:
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Check accounting figures and financial reports
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Prepare standard declaration form 03/TNDN – 04/TNDN
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Support electronic submission and valid record keeping
Conclusion: Pay taxes on time – declare properly to operate your business effectively
Filing and paying corporate income tax is a recurring task every quarter and every year, but it is a vital element in business management. From determining the correct declaration form, deadlines to electronic payment methods – everything needs to be absolutely accurate. If your business wants to ensure legal compliance and optimize taxes, cooperating with a professional unit like MAN is a wise choice.
