The BIR CAS Acknowledgment Certificate Process Under RMC No. 5-2021
A business that adopts a Computerized Accounting System (CAS) no longer applies for a Permit to Use (PTU) from the BIR — under Revenue Memorandum Circular (RMC) No. 5-2021, it registers the system with its Revenue District Office (RDO) by submitting a Checklist of Documentary Requirements, and the RDO issues an Acknowledgment Certificate within three working days of receiving the complete documents. This replaced a slower pre-2021 process that required a formal permit application and, in practice, a system demonstration before the BIR would approve it.
Keep Your Books BIR-Ready FREE →What changed under RMC No. 5-2021? #
RMC No. 5-2021, dated December 28, 2020, simplified how taxpayers register a Computerized Accounting System (CAS), Computerized Books of Accounts (CBA), or components such as an Electronic Storage System (ESS) or middleware. The circular removed the requirement to secure a Permit to Use before relying on the system, removed BIR Form No. 1900 from the application, and dropped the pre-approval system demonstration that RDOs previously required. The circular itself states the change plainly:
“All taxpayers intending to use CAS, CBA and/or its components, including the ESS, middleware and other similar systems shall not be required to secure Permit to Use (PTU).”
In place of a permit, the taxpayer now registers the “System” by submitting a Checklist of Documentary Requirements (CDR) to the RDO where the taxpayer-user of the system is registered — a sworn statement, a system description summary, and sample print-outs of the invoices or receipts the system generates, formatted to comply with the applicable Revenue Regulations. This is the same circular covered from a different angle in Do You Need a BIR Permit to Use (PTU) for Excel-to-DAT Conversion Software?, which explains why a tool that only reformats data for submission — rather than recording sales — falls outside CAS registration entirely.
Old PTU process vs. the RMC No. 5-2021 Acknowledgment Certificate process #
The pre-2021 process treated every CAS like a system the BIR had to approve before use, with a permit, a required form, and often a site visit; RMC No. 5-2021 replaced that with a document submission acknowledged, not approved, by the RDO. The table below lines up the two processes side by side.
| Step | Old PTU process (pre-RMC No. 5-2021) | RMC No. 5-2021 Acknowledgment Certificate process |
|---|---|---|
| Application form | BIR Form No. 1900 required | Not required |
| System evaluation | Pre-use demonstration/evaluation by the RDO | Not required |
| What the taxpayer submits | Formal PTU application with supporting documents | Checklist of Documentary Requirements (CDR): sworn statement, system description, sample print-outs |
| What the BIR issues | Permit to Use (PTU), often after a lengthy review | Acknowledgment Certificate (AC) |
| Timeline | No fixed statutory turnaround; approvals could take weeks | 3 working days from receipt of complete documents by the RDO |
| Where filed | RDO where the taxpayer is registered | RDO where the taxpayer-user of the system is registered |
Which businesses need to go through this process? #
Any taxpayer that adopts a CAS, CBA, or a qualifying component — such as an e-invoicing module, an inventory system that feeds the books, or middleware connecting a point-of-sale terminal to accounting records — must register that system with its RDO, regardless of business size, once the software takes over recording official transactions. BIR Books of Accounts: Manual, Loose-Leaf, and Computerized Accounting System Requirements covers the broader threshold question of when a CAS becomes mandatory (generally once gross sales exceed ₱3,000,000 or a POS system is required); this post picks up from there and focuses on the registration mechanics once that threshold is crossed or a business chooses CAS voluntarily.
Did the EOPT Act change whether you need a new Acknowledgment Certificate? #
Yes, for a specific group of taxpayers — the Ease of Paying Taxes (EOPT) Act and its implementing Revenue Regulations (RR) No. 7-2024 and RR No. 11-2024 required VAT taxpayers selling services, who had already registered a full CAS with e-receipting or e-invoicing before April 27, 2024, to revisit their systems for EOPT compliance, since the law shifted the tax base for services from official receipts to sales invoices. Where that shift affected the financial logic of the system — for example, a system still generating official receipts instead of invoices — the taxpayer had to reconfigure it and, per Grant Thornton’s tax alert on the issue, apply for a new Acknowledgment Certificate treated as if filing a fresh registration, with a compliance deadline of December 31, 2024. Taxpayers whose existing system could already issue invoices and required no change to its financial mechanics were not required to secure a new AC on that basis alone. If your CAS was registered before the EOPT Act and you haven’t confirmed which category it falls into, that’s worth resolving before your next audit, since an outdated AC on a reconfigured system is a mismatch a BIR examiner can flag.
A worked example: switching from manual books to cloud accounting software #
A small retail business currently keeps manual books of accounts and decides to move to a cloud-based bookkeeping platform to track sales, purchases, and inventory. Before relying on the new system for its official records, the owner:
- Confirms the software generates invoices and reports compliant with current BIR invoicing rules.
- Prepares the sworn statement and system description summary required under the CDR.
- Prints sample invoices generated by the platform to submit as part of the documentary requirements.
- Files the complete CDR package with the RDO where the business is registered.
- Receives the Acknowledgment Certificate within three working days of the RDO confirming the documents are complete — no demonstration, no BIR Form 1900, and no waiting on a separate permit approval.
Once the AC is issued, the business can retire its manual ledgers for the covered records, subject to the retention rules in How Long to Keep BIR Form 2307 and DAT File Records, which apply to electronic books just as they do to paper ones — the format changes, but the five-year preservation obligation does not.
Summary #
RMC No. 5-2021 replaced the old CAS Permit to Use with an Acknowledgment Certificate issued by the RDO within three working days of a complete document submission, cutting out BIR Form No. 1900 and the pre-use system demonstration that used to slow the process down. That simplification still stands for most CAS users, but the EOPT Act’s 2024 invoicing changes forced a subset of VAT taxpayers on services — those with a pre-April 2024 CAS still tied to official receipts — to reconfigure and, in many cases, secure a new AC by the end of 2024. Confirm which category your system falls into, keep the CDR documents on file alongside your AC, and pair this with BIR Books of Accounts: Manual, Loose-Leaf, and Computerized Accounting System Requirements for the threshold question of when CAS registration becomes mandatory in the first place.