What is a computerized accounting system (CAS)?

A computerized accounting system is software a business uses to record transactions, post to the general ledger, keep its books of accounts, and generate financial reports and — in a full CAS — sales invoices and official receipts. In the Philippines it must be registered with the BIR before you rely on it for tax purposes.

What is the difference between a CAS and a CBA?

A Computerized Books of Accounts (CBA) is software that keeps the books — ledgers and journals — in electronic form. A Computerized Accounting System (CAS) does that and also issues the principal and supplementary invoices and receipts. The BIR reviews the invoicing component of a CAS, so the registration is broader.

Do I need to register my accounting software with the BIR?

Yes, if it produces your books of accounts or issues your invoices and receipts. You file an application with your RDO or Large Taxpayers office under RMC 5-2021 and RMO 9-2021, and the BIR issues an Acknowledgement Certificate. Running unregistered system-generated books or invoices exposes you to penalties.

Is there still a Permit to Use (PTU) for a CAS?

No. Under RMC 5-2021 the BIR no longer requires a Permit to Use for a CAS — the old PTU with its mandatory system demonstration was done away with. The BIR now issues an Acknowledgement Certificate (AC) on submission of the documentary requirements, and the system is subject to post-evaluation during a tax audit rather than pre-approval.

What is an Acknowledgement Certificate (AC)?

An Acknowledgement Certificate is the document the BIR issues to confirm it has received and acknowledged your CAS or CBA registration. It replaced the old Permit to Use. Because approval is no longer based on a pre-use demo, the system must genuinely comply — the BIR can examine it later during an audit.

What documents do I need to register a CAS with the BIR?

Typically a sworn statement (with the summary of system description and forms/records specification), sample printouts of the principal and supplementary invoices/receipts, sample printouts of the books of accounts, a printed copy of the audit trail, and the accomplished Standard Functional and Technical Requirements document. A company profile and system description support the application.

Does RR 11-2025 require my CAS to send data to the BIR?

For covered taxpayers, yes. RR 11-2025 requires electronic invoices to be transmitted to the BIR for electronic sales reporting. An invoice from a CAS, CBA, POS, or invoicing software that is merely printed on paper, without the capability or readiness to electronically report the sales and invoice data, does not qualify as an electronic invoice — it is treated as a traditional, manually issued invoice. The mandatory-compliance deadline is 31 December 2026.

Who is covered by the RR 11-2025 e-invoicing rule?

The covered taxpayers include those engaged in e-commerce or internet transactions, taxpayers under the Large Taxpayers Service, taxpayers classified as Large Taxpayers under RA 11976, and businesses already using a CAS, CBA, or invoicing software. Micro taxpayers are exempt from the mandatory requirement. The rule implements the CREATE MORE Act (RA 12066) amendments to the Tax Code.

Do I need to re-register if I change my accounting system?

A major enhancement — a new module, a change in invoice or receipt format or numbering, or a switch of underlying software — generally requires a new application. Minor or cosmetic changes do not require re-registration but should be reported to the BIR in writing.

Can I claim a tax deduction for adopting e-invoicing?

Under the CREATE MORE Act, taxpayers who adopt e-invoicing and electronic sales reporting may claim an additional deduction for the cost of setting up the electronic sales reporting system, on top of the ordinary deduction — 100% of the cost for micro and small taxpayers and 50% for medium and large taxpayers. It can be availed only once, in the taxable year the system is completed or final payment is made.

Computerized Accounting System & BIR CAS: PH Guide

A computerized accounting system (CAS) keeps your books of accounts and issues invoices and financial reports in software, instead of on paper.

By the Orkids engineering team · Reviewed against BIR RMC 5-2021, RMO 9-2021, RR 11-2025 (as amended by RR 26-2025), and EOPT (RA 11976) issuances · Updated June 2026

Table of contents

01What does a computerized accounting system actually do?
02CAS vs Computerized Books of Accounts (CBA): what the BIR distinguishes
03BIR CAS accreditation: from Permit to Use to the Acknowledgement Certificate
04When you must re-apply: major vs minor system changes
05RR 11-2025: e-invoicing and sales-data transmission to the EIS
06Buying a CAS vs building one for a Philippine enterprise
07FAQ
08Key terms
09Sources

What counts as a computerized accounting system to the BIR
Component	What it does	BIR relevance
Accounting/bookkeeping module	Records transactions and posts to the general ledger	Produces the computerized books of accounts (CBA)
Invoicing module	Issues sales invoices and official receipts	Must use BIR-registered numbering and formats
Reporting module	Generates financial statements and BIR reports	Source of the books and schedules an examiner inspects
Sales-data transmission	Sends invoice data to the BIR's EIS	Required of covered taxpayers under RR 11-2025

A CAS can be a single integrated system or several linked modules (sales, purchases, inventory, payroll, GL). The BIR treats the whole set that produces your books and invoices as the system to be registered.

What does a computerized accounting system actually do?

A computerized accounting system replaces manual or spreadsheet bookkeeping with software that records each transaction once and posts it everywhere it needs to go. You enter a sale, and the system debits a receivable, credits revenue, computes the VAT, updates inventory, and rolls the figure into the trial balance and financial statements without re-keying.

The point is not speed alone. A CAS enforces double-entry rules, keeps an audit trail of who changed what, and produces the books of accounts and reports in a consistent form. In the Philippines that last part matters most: the books a CAS generates are the same books the Bureau of Internal Revenue examines, so the system is as much a compliance instrument as an accounting tool.

Core functions of a CAS

General ledger and double-entry posting
Accounts receivable and accounts payable
Sales invoicing and official-receipt issuance
Inventory and cost of goods sold
VAT and withholding-tax computation
Financial statements, trial balance, and BIR schedules
An audit trail and user-access controls

CAS vs Computerized Books of Accounts (CBA): what the BIR distinguishes

The choice is not academic. Registering the wrong type, or treating invoicing software as mere bookkeeping, is a common reason a registration is bounced back.

CAS vs CBA vs loose-leaf vs manual books
Method	What it covers	BIR treatment
Manual books	Handwritten journals and ledgers	Registered/stamped before use
Loose-leaf	Printed computer output bound as books	Needs a Permit to Use loose-leaf
CBA	Books of accounts kept in software	Registered; Acknowledgement Certificate
CAS	Books plus invoicing/receipts in software	Registered; Acknowledgement Certificate

Most growing Philippine businesses move from manual or loose-leaf to a CAS or CBA once transaction volume makes paper books impractical or once they need to issue system-generated invoices.

BIR CAS accreditation: from Permit to Use to the Acknowledgement Certificate

The biggest change taxpayers get wrong is that BIR "accreditation" of a CAS no longer works the way older guides describe. The old Permit to Use (PTU), which required a live system demonstration before a BIR evaluation team, was removed — a CAS no longer needs a Permit to Use at all. Under RMC 5-2021 (and the application guidelines in RMO 9-2021), the BIR instead issues an Acknowledgement Certificate (AC) once you submit the required documentation.

In practice you file the application with the Revenue District Office (RDO) or Large Taxpayers office where you are registered, attach the documentary requirements, and the BIR issues an Acknowledgement Certificate — not a permit, and not a pass after a demo. The system is then subject to post-evaluation during a tax audit rather than pre-approval. This makes onboarding faster, but it shifts the burden onto you: the system has to genuinely comply, because the BIR can examine it later and assess penalties if it does not.

Typical documentary requirements for a CAS/CBA application

The prescribed BIR application form for system registration
A company profile and a written system description and overview
A summary of the system's functions, features, and the modules covered
Sample print copies of system-generated invoices, receipts, and books of accounts
A sworn statement / affidavit attesting to the system and its features
Backup, archiving, and audit-trail procedures

When you must re-apply: major vs minor system changes

An Acknowledgement Certificate is tied to the system you described, so the BIR cares about changes. A major enhancement — a new module, a change in the invoice or receipt format, a different numbering scheme, or a switch in the underlying software — generally requires a fresh application, and you are expected to surrender the old AC and obtain a new one for the changed system.

A minor change — a bug fix, a cosmetic tweak, a non-functional update — does not require re-registration but should be documented. The safe rule: if a change touches how invoices are issued, how the books are produced, or how data is stored and transmitted, treat it as major and notify the BIR. Running materially different software than the one on file is the kind of gap an examiner looks for.

RR 11-2025: e-invoicing and sales-data transmission to the EIS

From 2025 the CAS conversation became inseparable from e-invoicing. Revenue Regulations No. 11-2025, issued 27 February 2025, implements Sections 237 and 237-A of the Tax Code as amended by the CREATE MORE Act (RA 12066). It requires covered taxpayers to issue electronic invoices and transmit the invoice data electronically to the BIR's Electronic Invoicing System (EIS).

Crucially, the regulation says an invoice generated by a CAS, CBA, POS, or invoicing software is not an electronic invoice unless the system can transmit the required data to the BIR. So a CAS that produces clean books but cannot connect to the EIS is no longer enough for covered taxpayers. The mandatory-compliance deadline, originally one year from effectivity, was extended by RR 26-2025 to 31 December 2026, and the first covered phase includes large taxpayers, taxpayers under the Large Taxpayers Service, e-commerce sellers (excluding micro taxpayers), and businesses already using a CAS, CBA, or invoicing system.

There is an incentive to move early. Under CREATE MORE, taxpayers who adopt e-invoicing and sales reporting may claim an additional deduction for the implementation cost — 100% for micro and small taxpayers and 50% for medium and large taxpayers — on top of the ordinary deduction.

What RR 11-2025 means for your CAS

Covered taxpayers must issue system-generated electronic invoices, not just printed ones
The system must transmit the required invoice data to the BIR's EIS
A CAS that cannot transmit does not produce a valid electronic invoice for covered taxpayers
Mandatory compliance for the first phase is set for 31 December 2026 (RR 26-2025)
Early adopters can claim a CREATE MORE additional deduction (100% micro/small, 50% medium/large)

Buying a CAS vs building one for a Philippine enterprise

For a single entity with standard books, an off-the-shelf accounting package that is already set up for BIR registration and EIS transmission is usually the right call — it is cheaper and faster than building. The calculus changes for groups with multiple entities, inter-company transactions, unusual revenue recognition, or industry workflows a generic product cannot model.

At that scale two costs compound: per-user and per-entity subscription fees, and the cost of bending your operation to fit the software. The alternative is a system shaped around your books and your BIR obligations — registered for an Acknowledgement Certificate, EIS-ready under RR 11-2025, and owned outright. That build-versus-buy decision, with BIR compliance built in from the first invoice, is the work Orkids does for Philippine enterprises.

What is a computerized accounting system? — frequently asked questions

What is a computerized accounting system (CAS)?: A computerized accounting system is software a business uses to record transactions, post to the general ledger, keep its books of accounts, and generate financial reports and — in a full CAS — sales invoices and official receipts. In the Philippines it must be registered with the BIR before you rely on it for tax purposes.
What is the difference between a CAS and a CBA?: A Computerized Books of Accounts (CBA) is software that keeps the books — ledgers and journals — in electronic form. A Computerized Accounting System (CAS) does that and also issues the principal and supplementary invoices and receipts. The BIR reviews the invoicing component of a CAS, so the registration is broader.
Do I need to register my accounting software with the BIR?: Yes, if it produces your books of accounts or issues your invoices and receipts. You file an application with your RDO or Large Taxpayers office under RMC 5-2021 and RMO 9-2021, and the BIR issues an Acknowledgement Certificate. Running unregistered system-generated books or invoices exposes you to penalties.
Is there still a Permit to Use (PTU) for a CAS?: No. Under RMC 5-2021 the BIR no longer requires a Permit to Use for a CAS — the old PTU with its mandatory system demonstration was done away with. The BIR now issues an Acknowledgement Certificate (AC) on submission of the documentary requirements, and the system is subject to post-evaluation during a tax audit rather than pre-approval.
What is an Acknowledgement Certificate (AC)?: An Acknowledgement Certificate is the document the BIR issues to confirm it has received and acknowledged your CAS or CBA registration. It replaced the old Permit to Use. Because approval is no longer based on a pre-use demo, the system must genuinely comply — the BIR can examine it later during an audit.
What documents do I need to register a CAS with the BIR?: Typically a sworn statement (with the summary of system description and forms/records specification), sample printouts of the principal and supplementary invoices/receipts, sample printouts of the books of accounts, a printed copy of the audit trail, and the accomplished Standard Functional and Technical Requirements document. A company profile and system description support the application.
Does RR 11-2025 require my CAS to send data to the BIR?: For covered taxpayers, yes. RR 11-2025 requires electronic invoices to be transmitted to the BIR for electronic sales reporting. An invoice from a CAS, CBA, POS, or invoicing software that is merely printed on paper, without the capability or readiness to electronically report the sales and invoice data, does not qualify as an electronic invoice — it is treated as a traditional, manually issued invoice. The mandatory-compliance deadline is 31 December 2026.
Who is covered by the RR 11-2025 e-invoicing rule?: The covered taxpayers include those engaged in e-commerce or internet transactions, taxpayers under the Large Taxpayers Service, taxpayers classified as Large Taxpayers under RA 11976, and businesses already using a CAS, CBA, or invoicing software. Micro taxpayers are exempt from the mandatory requirement. The rule implements the CREATE MORE Act (RA 12066) amendments to the Tax Code.
Do I need to re-register if I change my accounting system?: A major enhancement — a new module, a change in invoice or receipt format or numbering, or a switch of underlying software — generally requires a new application. Minor or cosmetic changes do not require re-registration but should be reported to the BIR in writing.
Can I claim a tax deduction for adopting e-invoicing?: Under the CREATE MORE Act, taxpayers who adopt e-invoicing and electronic sales reporting may claim an additional deduction for the cost of setting up the electronic sales reporting system, on top of the ordinary deduction — 100% of the cost for micro and small taxpayers and 50% for medium and large taxpayers. It can be availed only once, in the taxable year the system is completed or final payment is made.

Key terms

Computerized Accounting System (CAS): Software that keeps a business's books of accounts and issues its invoices and receipts; in the Philippines it must be registered with the BIR before use.
Computerized Books of Accounts (CBA): Software used mainly to keep the books — ledgers and journals — in electronic form, without necessarily issuing invoices; registered with the BIR like a CAS.
Acknowledgement Certificate (AC): The document the BIR issues to confirm registration of a CAS or CBA. It replaced the older Permit to Use and is issued on submission of the documentary requirements.
Permit to Use (PTU): The former BIR authorisation to use a CAS, which required a system demonstration before an evaluation team. It was suspended in favour of the Acknowledgement Certificate.
EIS: The BIR's Electronic Invoicing System, to which covered taxpayers must transmit invoice data under RR 11-2025.
RR 11-2025: Revenue Regulations No. 11-2025, issued 27 February 2025, implementing the electronic-invoicing and sales-data-transmission rules under the CREATE MORE Act amendments to the Tax Code.
CREATE MORE Act (RA 12066): The law amending the Tax Code's invoicing provisions; it underpins RR 11-2025 and grants an additional deduction for the cost of adopting e-invoicing.
Audit trail: A system record of who entered or changed each transaction; required of a registered CAS so the BIR can verify the integrity of the books.

Sources

Bureau of Internal Revenue — Revenue Memorandum Circular No. 5-2021 (simplified policies on the registration of CAS, CBA, and components, replacing the Permit to Use with an Acknowledgement Certificate).
Bureau of Internal Revenue — Revenue Memorandum Order No. 9-2021 (guidelines and procedures for processing CAS/CBA registration and issuing the Acknowledgement Certificate).
Bureau of Internal Revenue — Revenue Regulations No. 11-2025 (issued 27 February 2025), as amended by RR No. 26-2025 (electronic invoicing and sales-data transmission to the EIS; mandatory first-phase compliance by 31 December 2026), implementing Sections 237 and 237-A of the Tax Code as amended by the CREATE MORE Act (RA 12066).
Republic Act No. 11976 (Ease of Paying Taxes Act) and its implementing regulations on invoicing and bookkeeping.

Last reviewed June 2026

What is a computerized accounting system?

A computerized accounting system (CAS) is the software a business uses to record transactions, post to the general ledger, keep its books of accounts, and generate financial reports and BIR-compliant invoices automatically.