GDT e-VAT in Cambodia: what every business owner needs to know

What is GDT e-VAT?

'GDT e-VAT' is what Cambodian finance teams call filing VAT electronically with the General Department of Taxation, and it is worth being precise about the plumbing, because vendors selling against it often are not. GDT runs no separate system called e-VAT. VAT is declared inside GDT's ordinary monthly tax return, submitted through the E-Filing web and desktop applications that sit under GDT e-Tax Services at tax.gov.kh. That one monthly return carries VAT, withholding tax (WHT), Tax on Salary, and the 1% prepayment of Tax on Income. Alongside it, and separate from it, sits CamInvoice: the invoice-level e-invoicing platform operated by the General Department of Digital Economy (GDDE) since 2025. Any business registered for VAT files the monthly return; smaller businesses may register voluntarily but most stay below the threshold.

Before E-Filing, businesses submitted paper returns at GDT branch offices, and that route still exists on the earlier deadline. Moving submissions online retained the same legal structure: a taxable period of one calendar month, a return covering output VAT, input VAT credits, and net VAT payable, and the same supporting records. What electronic filing adds is structured data fields, a login to the e-Tax portal, five extra days on the deadline, and an audit trail tied to each submission reference number.

Who must file e-VAT in Cambodia?

The KHR 250 million figure quoted everywhere locally is not the VAT registration threshold, and the distinction matters if you are deciding whether you are in scope. KHR 250 million (roughly USD 62,000) is the floor of the small-taxpayer classification under Prakas No. 009 MEF.Prk of 12 January 2021. VAT registration is triggered separately, under Sub-Decree No. 49 of 11 March 2024: taxable turnover above KHR 125 million on goods or KHR 60 million on services across three consecutive months, or a government contract above KHR 30 million, with registration due within 15 days of becoming a taxable person. In practice that captures most of the formal sector: trading companies, manufacturers, importers, service firms, and NGOs with commercial operations. On cadence, note there are two deadlines and vendors often quote only one: the monthly return is due by the 25th of the following month when submitted through GDT's E-Filing system, or by the 20th when filed on paper at a branch office. The e-filing extension dates from Instruction No. 003 MEF of 27 February 2020; the statutory 20-day rule was never repealed. If the deadline falls on a weekend or public holiday it rolls to the next working day.

• VAT-registered: firms past the registration trigger (over KHR 125M on goods or KHR 60M on services across three consecutive months, or a government contract over KHR 30M), registering within 15 days.
• Monthly deadline: 25th of the following month for E-Filing, 20th for paper filing at a branch office.
• Late filing: additional tax of 10% of the underpaid amount plus 1.5% interest per month, rising to 25% where the shortfall exceeds 10% of the tax due or payment is still outstanding 15 days after a reminder letter, and 40% on a unilateral assessment (Law on Taxation 2023, Articles 223, 224 and 233).
• Withholding tax (WHT): declared monthly on the same portal and the same deadline. Resident payments are withheld at 15% on services, royalties, and interest, and 10% on rental; any Cambodian-source payment to a non-resident is withheld at 14%. Bank deposit interest paid to residents is 6% on fixed-term and 4% on savings.
• Tax on Salary (ToS): also monthly, same portal, same deadline. Note this is the employment tax; Tax on Income (ToI) is the separate annual business income tax.
• Voluntary VAT registrants: bound by the same filing obligations once registered.

How does a system prepare the monthly return?

No system files the monthly return for you. A person files it, your accountant or finance team, through GDT's E-Filing or the GDT Taxpayer App. What a system can do is the work that comes before the filing. The system we build keeps the books in KHR at the official rate and produces the monthly return figures and the sales and purchase lists, ready for your accountant to file through GDT's E-Filing. We call these filing-ready figures. Keep one distinction in view, because many businesses confuse the two: CamInvoice, the GDDE's invoice-level e-invoicing platform, is a separate system, and it is the one that does have an API. CamInvoice becomes relevant when you invoice a government counterparty already covered by the MEF circulars, or if and when a B2B mandate is published.

How much Cambodian tax setup a packaged accounting or ERP platform ships differs, so check it. Getting to return figures is configuration and bookkeeping discipline, not a connection to GDT: a tax code for each VAT treatment and each withholding tax rate you incur, KHR amounts converted at the National Bank of Cambodia rate that applies to each purpose, and every figure on the return tied back to a journal entry in the books.

Upstream of the ledger, what a CRM hands to the invoice and what it never writes marks where the sales record stops and the tax record starts. For the ledger itself, see our accounting system solutions. If you have not yet chosen the system that will keep the books, start with our ERP in Cambodia guide.

How does CamInvoice fit in?

CamInvoice is the GDDE's real-time e-invoicing platform. It is distinct from GDT's monthly return, and it is the government system that does have an API. It was officially launched on 12 May 2025. Where the monthly return covers a whole month and is filed by a person, CamInvoice requires invoice-level submission in real time: each invoice is posted to GDDE's platform at point of issuance, validated, and returned with a unique CamInvoice reference number that must appear on the invoice sent to the buyer. Mandatory rollout phasing for private-sector B2B transactions has not been formally published as of this writing. GDDE has indicated phased adoption starting with B2G, then large enterprises, then SMBs.

For businesses choosing or building a system now, it is worth scoping CamInvoice readiness at the same time. The monthly return and CamInvoice draw on some of the same data (TIN, invoice date, KHR amounts), but only CamInvoice is a connection between systems: it authenticates with OAuth 2.0 and takes each invoice through its API. First-mover advantage matters here: the partner-registration process for CamInvoice integration is currently open, and businesses that certify their integration early will be ahead of the compliance window when mandatory dates are announced.

Common pitfalls in Cambodia e-VAT compliance

These are the failure modes that catch Cambodian businesses on the monthly return: not the obvious ones but the ones that produce silent errors and audit exposure:

• KHR rounding drift across multi-currency books: USD invoices converted to KHR at slightly different rates in the accounting system versus the filing produce cent-level mismatches that accumulate into filing discrepancies over 12 months. The fix is to lock conversion to the correct declared rate for each purpose (NBC daily rate on invoices, NBC month-end rate on the monthly declaration, per Instruction 26118) and round in KHR, not USD.
• WHT misclassification by counterparty and payment type: the rate depends on both who you are paying and what for (15% on services, royalties, and interest paid to residents; 10% on rental; 14% on any Cambodian-source payment to a non-resident), and the classification must match GDT's TIN records. Services billed by a registered taxpayer against a valid VAT invoice fall outside the 15%, which is the exclusion most often missed. A foreign-managed local entity classified incorrectly can generate WHT shortfall notices years after filing.
• TIN registration mismatches: the TIN on every invoice line in a GDT filing must match the TIN held in GDT's registry at the time of filing. Businesses that change their registered name or address without updating GDT records find that historical filings no longer match GDT's records in an audit.
• Multi-warehouse invoice ordering: firms with multiple stock locations that raise invoices from different points generate ordering conflicts unless the numbering is coordinated centrally. GDT expects serial numbers in chronological order, restarting each tax year, with branch prefixes allowed only to identify a location. Gaps are not expressly prohibited by any instrument, but they read as a red flag in an audit, so treat them as something to explain rather than something to ignore.
• Late-filing penalty base: additional tax under Article 233 runs on the underpaid tax, and Article 66(2) defines VAT payable as output tax less the input credit allowed for the same period, so input VAT reduces the base rather than gross output VAT setting it. Firms that provision on gross tie up cash they never owed. Watch the credit window too: Sub-Decree 49 of 2024 allows input tax to be claimed in the same month or within 60 days, so a late-arriving supplier invoice can still be credited.
• Audit trail completeness across the retention window: the Law on Accounting and Auditing 2016 requires accounting records to be kept for ten years from creation (Article 23), and the 2023 Law on Taxation requires medium and large taxpayers to keep tax records for ten years, small taxpayers three (Article 201). GDT can audit any return within that window. A system that keeps the figures that were filed but not the journal entries behind them leaves a gap that is expensive to reconstruct a decade later.
• CamInvoice reference number missing from buyer invoices: once CamInvoice is in scope, every issued invoice must carry the GDDE-issued reference number. Businesses that issue invoices before the CamInvoice submission completes, or that batch-submit after the fact, will have issued non-compliant documents to buyers.

Frequently asked questions

These are the questions we get most often from Cambodian business owners and finance teams about the monthly return:

Can I file quarterly instead of monthly?

No. Under current GDT rules, VAT-registered businesses file monthly. The return covers the full calendar month and is due the 25th of the following month. Quarterly filing is not available for standard VAT registrants.

Do multi-entity groups file consolidated or separate returns?

Separate. Each legal entity with its own TIN files its own monthly VAT return. Consolidated group filing is not available in Cambodia's current GDT system. Inter-company transactions must be arm's-length and disclosed per entity.

How do we handle foreign-currency invoices in GDT filings?

All GDT amounts are reported in KHR, but there is no single rate. Under GDT Instruction No. 26118 (28 October 2022) the rate depends on what you are converting: an invoice uses the NBC daily official rate for the invoice date (a market rate is acceptable if it is not lower than NBC's, and a non-working day falls back to the preceding day); Tax on Salary uses the NBC rate on the 15th of the month; the monthly tax declaration uses the NBC rate on the last day of the month; the annual declaration uses the rate on 31 December. Applying one rate to all four is a common source of filing discrepancies, and the older practice of using an average rate for monthly and annual returns is obsolete.

What audit trail format does GDT expect?

GDT does not mandate a specific audit trail file format, but during an audit it will request the source documents (invoices, purchase orders, bank statements) that support each filed line. The Law on Accounting and Auditing 2016 requires these to be retained for ten years in a form that allows re-creation of the original submission.

How do we select a partner for the system that keeps the books?

Look for a partner that can show you the monthly return figures their system produced for a live client, and that quotes fixed-price after a scoped discovery, not time-and-materials on an unknown spec. Ask specifically about WHT classification logic and multi-currency rounding; those are where gaps surface. A vendor who says their software files the return for you is describing something that does not exist: a person files it through GDT's E-Filing.

How does CamInvoice partner registration work?

You work with GDDE, the system's operator, and GDDE publishes two routes on e-invoice.gov.kh. A business connecting its own system meets the operator, signs an NDA, builds the integration, demonstrates the working system, then signs an MOU and becomes a member. An ERP or accounting-system supplier registered in Cambodia applies as a service provider: an application form, an NDA, technical testing with an information security checklist and system integration and user acceptance test documents, then a contract. GDDE lists both routes as free of charge, and neither page gives a lead time. See the CamInvoice integration guide.

Can I keep my existing accounting software and still file the monthly return?

Yes. The return is filed by a person through GDT's E-Filing, so filing does not depend on which software holds the books. What differs between systems is how much work it takes to get figures that are ready to file: KHR amounts at the official rate, and sales and purchase lists that tie to the ledger. The constraint is that your source system must produce clean, consistent invoice data. Systems with unbounded rounding behaviour or inconsistent TIN fields on supplier records create ongoing friction.

What happens if we stop filing after being registered?

A lapsed filing is treated as a nil return for the period. GDT can issue an estimated assessment based on prior-period filings and impose penalties plus interest. Extended non-filing can result in TIN suspension, which blocks filing and can trigger a full audit. De-registration from VAT is a formal process requiring GDT approval; you cannot simply stop filing.

Can software file the monthly return for us?

No, and that is one of the more useful things to know when you are comparing vendors. The monthly return is filed by a person, your accountant or finance team, through GDT's E-Filing or the GDT Taxpayer App. GDT publishes filing guidance and its e-Tax Services at tax.gov.kh, and we found no developer documentation there. CamInvoice, run by GDDE, is the government system that does have an API. That is why the right question to put to a vendor is not 'does your software file the return' but 'show me the monthly return figures your system produced for a live client'.