Vietnamese VAT e-invoices legally require the total amount to appear twice: once as a numeral and once spelled out in words, in a field commonly labeled “Bằng chữ” (literally “in words”). This isn’t a formatting suggestion — it is a required content field under Vietnam’s e-invoice regulations, and an invoice missing or mismatching it can be rejected during a tax audit or by the buyer’s accounting department, even if the numeral total is completely correct.
The Legal Basis: Why E-Invoices Require Both Formats
Vietnam’s e-invoicing regime is governed by Decree 123/2020/NĐ-CP and its implementing guidance, Circular 78/2021/TT-BTC, issued by the Ministry of Finance (Bộ Tài Chính). These regulations set out the mandatory content fields every e-invoice must contain — invoice number, issue date, seller and buyer tax codes, item description, quantity, unit price, VAT rate, VAT amount, and total payment amount — and the total payment amount field must include the written-word equivalent alongside the numeral.
For a foreign-owned business or an accountant unfamiliar with Vietnamese invoicing conventions, this can look like an unusual extra step compared to invoicing norms in the US or EU, where invoices are almost always numeral-only. But the requirement has the same underlying rationale seen in contract drafting globally: a spelled-out figure is much harder to alter undetected than a numeral, and Vietnam’s invoice regulations formalize that safeguard as a mandatory field rather than a best practice. On an e-invoice, the field also functions as an internal consistency check — invoicing software and the General Department of Taxation’s (Tổng cục Thuế) e-invoice verification portal can flag a submission where the numeral and word amounts don’t correspond to the same figure.
What the Amount-in-Words Field Actually Needs to Say
The field must state the total payment amount (post-VAT, i.e., the final amount the buyer owes) in Vietnamese words, following standard Vietnamese number-naming conventions. For an invoice total of 125,400,000 VND, the field should read:
“Một trăm hai mươi lăm triệu, bốn trăm nghìn đồng.” (One hundred twenty-five million, four hundred thousand dong.)
For businesses issuing invoices to both domestic and foreign customers, it’s common practice — though not universally mandated for every transaction — to also provide an English rendering underneath or alongside the Vietnamese line for the buyer’s internal accounting clarity, especially for foreign-invested enterprises whose finance teams report in English:
“One hundred twenty-five million, four hundred thousand Vietnamese Dong only.”
Where a contract or invoice is also denominated in a foreign currency (e.g., an export invoice priced in USD but referencing the VND-equivalent for domestic tax purposes), both the VND numeral/words pair and the foreign-currency numeral/words pair are typically shown, since Vietnamese tax authorities require the VAT calculation itself to be reflected in VND regardless of the invoice’s primary currency.
Rounding Conventions for VND Amounts
Vietnamese dong has no smaller circulating subunit in modern practice — unlike USD cents or EUR cents, invoice totals in VND are conventionally whole numbers with no decimal places. This affects both the numeral and the words field:
- Unit prices and line-item subtotals may carry decimal places during calculation (particularly when a unit price is derived from a foreign-currency conversion), but the final total payment amount on the invoice is rounded to the nearest whole dong before being written in both numeral and word form.
- Standard rounding is to the nearest unit (round-half-up in most accounting software), applied consistently across the invoice so the sum of line items reconciles with the stated total — a mismatch here, even a rounding difference of a few dong, is a common reason an e-invoice fails automated validation.
- The amount-in-words field should never include a fractional/decimal reference for a VND total (no “and 50 cents” equivalent), since there is nothing to spell out below the whole-dong level. If you see this on a VND invoice, it usually indicates a template copied from a USD/foreign-currency invoice format without adjusting for VND convention.
- For invoices genuinely denominated in a foreign currency with decimal subunits (USD, EUR), the amount-in-words field for that currency does spell out the decimal portion (e.g., “and fifty cents” or “and 50/100”), following the same convention used in contracts and checks.
Common Formatting Mistakes on Vietnamese E-Invoices
| Mistake | Why it’s a problem |
|---|---|
| Amount in words doesn’t match the numeral total | The most common rejection reason during accounting review or tax audit — often caused by editing the invoice total after the words field was already generated, without regenerating the words |
| Writing the pre-VAT subtotal in words instead of the post-VAT total | The words field should reflect the final payable amount (subtotal + VAT), not the pre-tax subtotal — a frequent error when invoicing software auto-fills from the wrong line |
| Leaving the amount-in-words field blank on a manually adjusted invoice | If an invoice is corrected or adjusted after initial issuance, the words field must be updated to match — a blank or stale words field can invalidate the corrected invoice |
| Using inconsistent Vietnamese number-naming style | Vietnamese has some regional/legacy variation in how numbers are read aloud (e.g., “mười lăm” vs. “mười năm” for 15) — invoicing software should follow the standard formal accounting convention, not casual spoken variants |
| Decimal cents shown on a VND-denominated total | Indicates a currency/format mismatch, as VND totals are not expressed with subunit decimals in standard invoicing practice |
| Missing the currency name in the words field | The words should specify “đồng” (dong) or “Vietnamese Dong” explicitly — omitting it makes the field ambiguous on multi-currency invoices |
Why This Matters More for Foreign-Owned Businesses
Foreign-invested enterprises and international accountants operating in Vietnam sometimes treat the amount-in-words field as a cosmetic legacy convention and either skip it in custom invoice templates or generate it inconsistently with automated tools not built for Vietnamese formatting rules. In practice, an e-invoice submitted to Vietnam’s e-invoice verification system with a missing, blank, or mismatched amount-in-words field can be rejected at submission, delaying revenue recognition and VAT deduction claims — and for the buyer’s side, an invoice with this defect may be challenged as invalid supporting documentation for their own input VAT credit. Building the field correctly into your invoicing workflow from the start avoids both problems.
Generate Correct Amount-in-Words Fields with DocWello
DocWello’s number-to-words converter converts a numeral VND (or USD/EUR) amount into properly formatted Vietnamese or English words instantly in your browser, matching the conventions Vietnamese e-invoices require, with no invoice data uploaded anywhere. This tool addresses the specific “Bằng chữ” compliance field on VAT invoices; if you’re instead drafting a large commercial contract and want to understand why contract sums are spelled out for fraud-prevention reasons rather than tax compliance, see our companion article on writing large contract sums in words, which covers that related but distinct use case.
Frequently Asked Questions
Is the amount-in-words field legally required on Vietnamese e-invoices?
Yes. Under Vietnam’s e-invoice regulations (Decree 123/2020/NĐ-CP, guided by Circular 78/2021/TT-BTC), the total payment amount must be stated in words as well as in numerals — it is a mandatory content field, not optional formatting.
Should the amount in words reflect the pre-tax subtotal or the total including VAT?
The final total payment amount, including VAT, should be spelled out in the words field — not the pre-VAT subtotal. Writing the pre-tax figure is a common error that creates a mismatch with the invoice’s stated total.
Are decimal amounts (cents) written out for VND invoices?
No. Vietnamese dong invoices are conventionally rounded to the nearest whole dong with no subunit decimals, so the amount-in-words field for a VND total should not include a fractional/cents portion. Foreign-currency invoices with decimal subunits (USD, EUR) do spell out the decimal amount.
What happens if the words and numeral amounts don’t match on an e-invoice?
The invoice can fail validation in Vietnam’s e-invoice verification system or be flagged during a tax audit, and the buyer’s accounting department may reject it as invalid supporting documentation for input VAT deduction. If an invoice total is corrected after issuance, the amount-in-words field must be updated to match.
Do foreign businesses invoicing in Vietnam need to provide an English translation alongside the Vietnamese amount in words?
It’s not universally mandated for every transaction, but many foreign-invested enterprises add an English rendering alongside the required Vietnamese “Bằng chữ” line for their own accounting clarity — the Vietnamese-language field remains the legally required one for compliance purposes.