Introduction
Businesses in the Philippines that plan to use a Computerized Accounting System (CAS) must follow the requirements set by the Bureau of Internal Revenue (BIR).
A CAS allows businesses to record financial transactions digitally and generate structured accounting records such as Service Invoices, Books of Accounts, Financial Reports, and Audit Trail logs.
Understanding the BIR requirements helps businesses prepare the necessary documents and ensure their accounting records are organized and traceable.
This guide explains the CAS requirements based on the BIR Citizen’s Charter and Revenue Memorandum Order (RMO) 9-2021.
What is CAS in BIR Context?
A Computerized Accounting System (CAS) is a system used to record financial transactions electronically instead of manual books.
CAS helps maintain structured financial documentation such as:
Service Invoices
Books of Accounts
Financial Reports
Transaction records
Audit Trail logs
Businesses may apply for CAS registration through the Online Registration and Update System (ORUS) provided by BIR.
Who May Apply for CAS?
According to the BIR Citizen’s Charter, CAS registration may be applied for by:
Large Taxpayers (LTs)
Non-Large Taxpayers (Non-LTs) engaged in business
Businesses that choose to use:
Computerized Accounting System (CAS)
Computerized Books of Accounts (CBA)
Electronic Storage System (ESS)
Middleware or similar systems
CAS is commonly used by businesses that want structured and organized financial records.
Where to Apply for CAS
CAS applications are processed through the:
Revenue District Office (RDO)
Large Taxpayer Office (LT Office)
Submission of requirements is done through:
BIR Online Registration and Update System (ORUS)
Applicants upload documentary requirements in:
PDF
JPEG
PNG
Maximum file size per upload:
25MB
BIR CAS Requirements Checklist (2026)
Based on RMO 9-2021 and BIR Citizen’s Charter, the following documents are typically required when applying for CAS registration:
1. Sworn Statement and System Description
Applicants must submit a Sworn Statement together with the Summary of System Description.
This document describes:
system functionality
forms generated
records maintained
reports available
Reference:
Annex C or Annex E of RMO 9-2021
Annex C-1 System Description
These forms are available from the BIR website.
2. Sample Print of Invoices or Receipts
Businesses must provide sample print copies of principal receipts or invoices generated by the system.
Invoices should comply with:
Revenue Regulations (RR) No. 16-2018
Examples include:
Service Invoice
Sales Invoice
Official Receipt
These documents demonstrate how transactions are recorded.
3. Sample Print of Books of Accounts
CAS must be capable of generating Books of Accounts compliant with:
Revenue Regulations (RR) No. 9-2009
Examples of Books of Accounts:
General Journal
General Ledger
These records show how transactions are organized and classified.
4. Audit Trail Logs
The system must provide an Audit Trail showing activity logs generated by the system.
Audit Trail may include:
record creation
record updates
transaction changes
user activity
Audit logs help maintain traceable and transparent accounting records.
5. Functional and Technical Requirements
Applicants must submit the accomplished Standard Functional and Technical Requirements document.
Reference:
Annex B of RMO 9-2021
This document describes how the system processes financial transactions and maintains accounting records.
6. Certification for System Usage (if applicable)
If the software license is under a parent company or affiliated company, certification may be required allowing the taxpayer to use the same system.
This confirms authorized use of the system.
Why Structured Accounting Records Matter
Maintaining organized accounting records helps businesses:
track financial transactions
maintain consistent documentation
generate financial reports
review transaction history
Structured accounting systems help ensure financial data is recorded in a consistent format.
This can improve visibility of financial activity and support organized reporting processes.
Common Components of a CAS
A typical computerized accounting system includes:
Service Invoice recording
Books of Accounts
Double-entry accounting structure
Financial Reports
Audit Trail logs
Customer transaction records
These components support structured financial record keeping.
CAS vs Manual Record Keeping
Manual recording of transactions using spreadsheets or notebooks may become difficult as business transactions increase.
CAS helps organize financial data in one system and provides structured recording of accounting entries.
Using a structured workflow can help maintain consistency of financial records.
How CAS Supports Financial Reporting
CAS allows businesses to generate reports based on recorded transactions such as:
Profit and Loss
Balance Sheet
Trial Balance
These reports summarize financial performance and transaction history.
Important Note
BIR does not generally endorse or certify specific software brands publicly.
CAS acknowledgement is issued after evaluation of:
submitted documents
system description
sample reports
functional capabilities
Businesses should ensure their system supports structured financial record keeping.
Conclusion
Understanding the BIR requirements for CAS helps businesses prepare documentation and maintain structured accounting records.
CAS provides a consistent method of recording Service Invoices, maintaining Books of Accounts, generating Financial Reports, and tracking transaction history.
Businesses that want organized financial documentation may consider implementing a computerized accounting system as part of their accounting workflow.