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When receiving payments in US dollars (USD) from Amazon, Etsy, Shopify, or overseas business customers, one common challenge for cross-border sellers when issuing invoices is determining which exchange rate to use when converting the amount into Vietnamese dong (VND).
On 14/9/2026, the Tax Department issued Official Letter 6810/CT-QLNT to clarify how the invoice exchange rate is determined. Understanding this guidance correctly helps businesses maintain consistent USD revenue figures across invoices, accounting records, and customs declarations, instead of having to explain each discrepancy when subject to inspection.
1. Why the invoice exchange rate is a risk point for many businesses
A USD transaction passes through at least three recording systems: e-invoices submitted to the tax authority, accounting records, and customs declarations for exported goods. Each system may use a different exchange rate, so the same number can result in three different VND amounts.
When the invoice exchange rate is not based on the correct legal grounds, declared revenue may differ from recorded revenue, resulting in the need to adjust invoices, file supplementary returns, or provide explanations when the tax authority cross-checks the data.
For e-commerce sellers, currency conversion becomes more complex as transaction volumes grow, with hundreds of orders each month, funds moving through multiple payment intermediaries, and often a gap of several days between the sale date and the payment date. In a cross-border business model like this, manually converting foreign-currency revenue in spreadsheets can easily lead to errors.
2. New regulations on invoice exchange rates from 01/7/2026
2.1 Decree 254/2026/ND-CP: recording foreign currencies and presenting exchange rates on invoices
Under Point c.1, Clause 8, Article 10 of Decree 254/2026/ND-CP, when a transaction arises in a foreign currency in accordance with foreign exchange laws, businesses may state the unit price, amount, value-added tax (Value Added Tax - VAT), and total payment amount in the foreign currency, together with the name of the foreign currency. At the same time, the invoice must show the exchange rate between the foreign currency and Vietnamese dong in accordance with the Law on Tax Administration and its guiding documents.
Decree 254 only refers to tax administration regulations without specifying the type of exchange rate, creating a gap that has led many exporters to understand that the exchange rate on the invoice must follow Clause 4, Article 14 of Decree 252/2026/ND-CP, i.e. the tax calculation exchange rate under customs regulations.
2.2 Official Letter 6810/CT-QLNT: actual transaction rate under accounting regulations
Official Letter 6810/CT-QLNT dated 14/9/2026 issued by the Tax Department clarified that the exchange rate shown on the invoice is the actual transaction rate (Actual Transaction Rate) determined under accounting regulations. The Tax Department based this on Clauses 1 and 5, Article 26 of Law on Tax Administration No. 108/2025/QH15, under which e-invoices must fully and truthfully reflect transactions in accordance with both tax laws and accounting regulations. The content of the official letter was reported by the Journal of Finance & Economics on 16/9/2026.
Therefore, the invoice exchange rate for USD revenue is determined under Circular 99/2025/TT-BTC and the current corporate accounting regime, rather than automatically using the customs exchange rate.
2.3 Two cases subject to specific rules
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Case where tax is declared in a foreign currency under Clause 1, Article 14 of Decree 252/2026/ND-CP: the currency used for tax declaration and payment, and the conversion exchange rate, shall be implemented in accordance with Article 14 of this Decree.
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Customs declarations for exported and imported goods: the customs-assessed value for tax purposes still uses the telegraphic transfer buying rate announced by the Head Office of Joint Stock Commercial Bank for Foreign Trade of Vietnam (Vietcombank) at the end of the Thursday immediately preceding the week, applicable to declarations registered during that week.
To compare the exchange-rate rules under Circular 99 and Decree 252 that were compiled before the official letter was issued, businesses can refer to the summary table on Thư Viện Pháp Luật. Businesses that have already issued invoices based on the previous interpretation should review them with their tax planning advisor before deciding whether any adjustment is necessary.
3. How to determine the bank exchange rate under Circular 99/2025/TT-BTC
Circular 99/2025/TT-BTC allows businesses to choose the actual transaction rate using one of two methods:
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• The average telegraphic transfer buying and selling rate of the commercial bank with which the business regularly transacts on the transaction date.
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• An approximate rate, provided that the difference does not exceed ±1% from the average telegraphic transfer buying and selling rate and does not materially affect the financial statements.
Formula:
Average telegraphic transfer buying and selling rate = (Telegraphic transfer buying rate + Telegraphic transfer selling rate) / 2
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Telegraphic transfer buying rate: the rate at which the bank purchases foreign currency through an account, as published on the transaction date.
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Telegraphic transfer selling rate: the rate at which the same bank sells foreign currency through an account on the same day.
Example (illustrative figures): on 10/9/2026, the bank with which the business regularly transacts quoted a telegraphic transfer buying rate of 26,200 VND/USD and a telegraphic transfer selling rate of 26,500 VND/USD. The average rate is 26,350 VND/USD, so an invoice for USD 5,000 would show an exchange rate of 26,350, corresponding to VND 131,750,000.
The key point is consistency, as changing the bank or method for each invoice will be difficult to explain during an inspection. Therefore, businesses should agree on one bank and one method to apply consistently throughout the accounting period, while retaining the daily published exchange-rate tables as supporting documents.
4. Determining the correct invoice issuance time and applicable exchange rate
The actual transaction rate is always tied to a specific date, so businesses must determine the correct time when the invoice issuance obligation arises before looking up the exchange rate. Article 9 of Decree 254/2026/ND-CP provides as follows:
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Transaction type
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Invoice issuance time
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Applicable exchange rate
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Domestic sale of goods
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The time when ownership or the right to use the goods is transferred, regardless of whether payment has been received
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Actual transaction rate on the invoice issuance date
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Export of goods (including export processing)
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Self-determined by the seller, no later than the next working day after the goods are cleared through customs
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Actual transaction rate on the invoice issuance date
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Provision of services (including to foreign organizations and individuals)
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The time when the service is completed; if payment is received in advance or during the provision of the service, the time of payment receipt
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Actual transaction rate on the invoice issuance date
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For advance payments received from customers, the portion of revenue corresponding to the amount received in advance applies the exchange rate on the advance receipt date; the remaining portion applies the exchange rate on the date the revenue is recognized. This accounting rule can easily be overlooked when sellers receive deposits from business customers (Business-to-Business - B2B).
For exported goods, the import-export and accounting departments need to clearly record the customs clearance date on the declaration. If this step is missed, the invoice may be issued late and the applicable exchange rate may differ from the required date.
5. Three exchange rates and how to handle the difference
5.1 Distinguishing exchange rates by purpose
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Criteria
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Invoice exchange rate
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Customs declaration exchange rate
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Accounting book exchange rate
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Basis
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Clause 4, Article 14 of Decree 252/2026, customs regulations
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Exchange rate type
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Actual transaction rate under accounting regulations
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Actual transaction rate or book rate
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Cut-off time
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Invoice issuance date
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End of the Thursday immediately preceding the week, used for the entire week
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Date the transaction arises
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Purpose
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Show the converted value on the e-invoice
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Calculate export and import taxes
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Record revenue, receivables/payables, and exchange gains/losses
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The Customs Department confirmed in guidance published by the Journal of Finance & Economics on 15/9/2026 that when the foreign-currency value is consistent, the difference in VND amounts between the customs declaration and other documents resulting from the use of different exchange rates is not considered a difference in the value of the goods, and businesses do not have to amend the declaration merely to make the VND figures match.
5.2 Handling exchange-rate differences when payment is received
Revenue is recognized at the exchange rate on the invoice date, but USD funds often reach the account several days, or even several weeks, later for platforms that settle on a cycle. When payment is received, the receivable is reduced using the book rate, while the funds received are recorded at the actual transaction rate on the receipt date. The resulting exchange-rate difference is accounted for as follows:
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• Exchange gain: recorded as Financial Income.
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• Exchange loss: recorded as Financial Expenses.
At the end of the reporting period, businesses must revalue foreign currency-denominated balances, such as USD bank deposits and outstanding USD receivables, using the exchange rate applicable on the reporting date. Any difference from the exchange rate currently recorded in the accounting books is temporarily recognized in Account 413 (Foreign Exchange Differences) and subsequently transferred to financial income if it results in a gain, or to financial expenses if it results in a loss. This accounting entry affects only the financial results and does not change the revenue already recorded on the invoice.
6. Foreign-currency revenue conversion process for cross-border sellers
To ensure that foreign currency revenue is converted consistently and to minimize discrepancies between invoices, accounting records, and marketplace data, cross-border sellers should establish a standardized process covering everything from exchange rate determination to periodic reconciliation.
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Select one commercial bank with which the business regularly transacts and one method (average or approximate within the ±1% range), and specify it in the internal financial regulations.
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Configure the e-invoice software to use the invoice exchange rate applicable to the correct issuance date, rather than using one fixed exchange rate for the entire month.
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Transfer the customs clearance date from the declaration to the accounting department so that export invoices are issued on time.
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Retain the daily published exchange-rate table as the original supporting document.
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Periodically reconcile revenue on invoices, accounting records, and the platform's Settlement Report to detect discrepancies early.
7. Standardizing invoice exchange rates for transparent USD revenue
GenInvoice helps e-commerce sellers automate the invoicing process using sales data, reducing manual work when handling large volumes of orders. For transactions in foreign currencies, GenInvoice automatically applies the appropriate exchange rate to each transaction, eliminating the need to manually convert individual orders before issuing invoices.
Accurate invoicing also depends on standardized and synchronized source data. Genbook centralizes sales and accounting data, providing a consistent data source for invoice preparation, review, and reconciliation. Contact Sliner for guidance on optimizing your e-invoicing process for cross-border e-commerce operations.
