Vietnam MST number guide
Mã số thuế – MST
The “Mã số thuế (MST)” is a tax identification number issued to entities (including companies, partnerships and subsidiaries) of relevance and to individuals for tax administration. An organisation or an individual can apply for MST number online by accessing the website of General Department of Taxation.
Format of the MST number
MST number either has 10 digits or 13 digits. Parent organisations and individuals have a 10 digit MST number. Subsidiaries have 13 digit MST number where the first 10 digits are the same as the parent organisation of this subsidiary.
Example:
10 digit number — 0314409058
13 digit number — 0314409058-002
Breaking down the MST number
03 — The first 2 digits of the MST number represent the province code where the business is established. If the business relocates to a different location in the future, the MST number remains unchanged.
1440905 — The next 7 digits can be any random number from 0000001 to 9999999.
8 — The 10th digit is the checksum that is calculated on the basis of the first 9 digits.
002 — The last 3 digits (in the 13 digit MST number) are optional and are used only for subsidiaries. They can be any random number from 001 to 999.
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Frequently Asked Questions
My Vietnamese client is withholding combined VAT and CIT from my invoice under FCT — do I actually owe both taxes even if my services are performed entirely outside Vietnam?
Yes. Vietnam's Foreign Contractor Tax (FCT) under Circular 103/2014/TT-BTC applies whenever a foreign entity without a licensed Vietnamese presence provides services to a Vietnamese contracting party, regardless of where the work is physically performed. The Vietnamese payer is legally obligated to withhold and remit both a VAT component (typically 5% on gross contract value for services) and a CIT component (typically 5% for most service contracts, 10% for royalties) on your behalf. The only escape routes are: registering a Vietnamese entity (branch or representative office) and filing taxes directly via the "hybrid" or "Vietnamese accounting" method, or invoking a Double Tax Agreement if one exists between your country and Vietnam and formally applying for treaty relief before payment is made. [1] [2]
Does a foreign SaaS or digital-platform company need to obtain a Vietnamese MST and register with the GDT, even without a local office?
Yes, and with no minimum-revenue threshold. Under Circular 80/2021/TT-BTC, overseas suppliers that conduct e-commerce or digital-platform business with Vietnamese customers must register directly with the General Department of Taxation (GDT) via its electronic tax portal, obtain a 10-digit MST, and file quarterly VAT returns. Vietnam's new VAT Law No. 48/2024/QH15 (effective July 1, 2025) raised the VAT rate on cross-border digital services from 5% to 10% and expanded the definition of taxable digital services. Failure to register shifts withholding liability to Vietnamese banks and payment intermediaries, who are required to identify and deduct the tax on transactions to unregistered foreign suppliers. [3] [4]
Our Vietnamese partner's MST shows as "ngừng hoạt động" (ceased operations) in the GDT lookup — can they still issue valid invoices or receive payments?
No. An MST with "ngừng hoạt động" (deactivated/ceased) status means the tax code has been officially suspended by the tax authority — typically triggered by license revocation, failure to file returns for consecutive periods, or the authority confirming no business activity at the registered address. Invoices issued under a deactivated MST are legally invalid and cannot be deducted as input costs by the payer. Reactivation requires the company to submit a formal application to its supervisory tax authority, settle all outstanding tax arrears and penalties, and obtain a decision restoring legal status before the MST becomes usable again. You can verify any company's current MST status for free at the GDT's public lookup tool. [5] [6]
My employee's payroll system shows two separate MST numbers for the same person — which one is valid after Vietnam's Circular 86 transition?
This is a known duplication issue that Circular 86/2024/TT-BTC was specifically designed to resolve. From July 1, 2025, Vietnamese citizens' 12-digit national citizen identification number (CCCD) replaces any separately issued personal tax code. Where an individual was inadvertently issued more than one MST, the taxpayer must update their national ID information with the GDT so that all legacy tax codes are merged into the single CCCD-linked identifier. The tax authority consolidates the records automatically once the update is submitted — no manual cancellation of the old codes is required. Old personal MST codes issued before July 1, 2025 remained valid through June 30, 2025 only. Employers must update payroll withholding records to use the CCCD as the authoritative PIT identifier. [7] [8]
We stopped issuing paper invoices but are getting fined — what did we miss about Vietnam's mandatory e-invoice rules?
Since July 1, 2022, paper invoices are no longer legally valid for any business, organization, or household taxpayer registered under the declaration method in Vietnam. The rules are set out in Decree 123/2020/ND-CP and Circular 78/2021/TT-BTC (superseded from June 1, 2025 by Circular 32/2025/TT-BTC). E-invoices must be issued with or without a tax-authority verification code depending on business type. Fines for issuing invoices incorrectly or failing to switch to e-invoices range from VND 10 million to VND 50 million per violation under Article 24 of Decree 125/2020/ND-CP. A common trap: e-invoices must be transmitted to the GDT system in real time for verification-code invoices — batching or back-dating transmissions is treated as a separate violation. [9] [10]
