Honduras Invoice Requirements: CAI System & Mandatory Fields

Every invoice issued in Honduras must carry a CAI (Codigo de Autorizacion de Impresion) — a unique authorization code that SAR, the Servicio de Administracion de Rentas, assigns to each batch of invoices before they can be printed or generated. Beyond the CAI itself, valid Honduras invoices require a set of mandatory fields: the taxpayer's 14-digit RTN (Registro Tributario Nacional), a 16-digit sequential invoice number, a line-item ISV tax breakdown at the standard 15% rate, and the CAI's expiration date. Invoices reach the market through one of two modalities — autoimpresor, where businesses self-print from SAR-registered systems, or imprenta, where SAR-certified printing companies produce the documents. Honduras is also progressively transitioning to electronic invoicing under the CAEE (Codigo de Autorizacion de Emision Electronica) system, which operates on a real-time clearance model.

This invoicing framework is formally known as the Regimen de Facturacion, Honduras's regulatory structure governing how fiscal documents are authorized, produced, and controlled. The system's legal foundation traces to Acuerdo 189-2014, which established the initial framework. The current governing regulation is Acuerdo 481-2017, a more expansive instrument that covers invoicing rules, fiscal document types, and the fiscal registry of authorized printing companies. SAR administers every component of this system, from CAI issuance to compliance enforcement.

For English-speaking finance professionals — whether you're processing payments to Honduran vendors, managing AP for a company operating in Honduras, or handling bookkeeping for Honduran clients — the Honduras invoice requirements present a specific challenge: virtually all detailed regulatory documentation exists only in Spanish-language sources published by SAR. This guide consolidates those requirements into a structured English-language reference, organized around the CAI authorization system that sits at the center of Honduran invoicing compliance.

How the CAI Authorization System Works

The CAI is not a static registration number. It is a per-batch authorization: each time a taxpayer needs to print a new set of invoices, they must request and receive a fresh CAI from SAR before any of those invoices become fiscally valid.

What a CAI Represents

When SAR approves a CAI request, it generates a unique alphanumeric code tied to three constraints:

An authorized invoice number range (from-to sequential numbers) that defines exactly which invoice numbers the taxpayer may issue under that CAI.
A validity expiration date (fecha limite de emision) after which no invoice bearing that CAI may be issued.
The specific taxpayer and establishment requesting the authorization.

An invoice printed with a number outside the authorized range is invalid. An invoice dated after the CAI's expiration is equally invalid, even if the number falls within range. Both conditions must be satisfied for the document to hold fiscal standing.

Requesting a CAI Through the Oficina Virtual

Taxpayers request new CAIs electronically through SAR's Oficina Virtual portal. The process is not automatic. SAR checks that the requesting taxpayer is current on all tax obligations before granting authorization. Outstanding omissions in tax filings, unpaid debts, or unresolved compliance issues will block the request. This prerequisite turns the CAI system into a passive enforcement tool: taxpayers who fall behind on their obligations lose the ability to issue valid invoices until they resolve their standing with SAR.

SAR Validation and Enforcement

Any invoice bearing a CAI can be verified against SAR's records to confirm it was legitimately authorized. This is the mechanism that gives the system its enforcement power. A buyer, auditor, or tax authority can check whether a CAI is genuine, whether the invoice number falls within the approved range, and whether the document was issued before the expiration date. Invoices that fail any of these checks lack fiscal validity and cannot support tax deductions or ISV credits.

Breaking Down the 16-Digit Invoice Number

Honduras invoice numbers follow a structured 16-digit format written as NNN-NNN-NN-NNNNNNNN. Each segment encodes specific information about the document's origin:

First 3 digits (NNN): The establishment or branch number. A business operating from a single location typically uses 000. Companies with multiple branches assign a distinct code to each physical location.
Next 3 digits (NNN): The punto de emision (emission point code) assigned by SAR. This identifies the specific invoicing terminal or point of sale within an establishment.
Next 2 digits (NN): The document type code. Standard invoices use 01. Other fiscal document types carry different codes in this position.
Final 8 digits (NNNNNNNN): The sequential correlative number within the authorized range for that CAI. This is the number that must fall within the from-to range specified in the CAI authorization.

When you examine a Honduras invoice, this numbering structure tells you which branch issued it, from which terminal, what type of fiscal document it is, and where it falls in the authorized sequence. If the correlative number exceeds the upper bound of the CAI's approved range, the invoice is unauthorized. Other Central American countries use parallel pre-authorization systems — Panama's CUFE invoice validation and authorization system follows a similar pattern.

Mandatory Fields on a Honduras Invoice

Acuerdo 481-2017 (Articles 10 and 11) defines every element that must appear on a valid Honduras invoice. These Honduras invoice mandatory fields fall into two categories: those pre-printed or auto-generated on the invoice form before any transaction takes place, and those completed at the moment of sale.

Pre-Printed or Auto-Generated Fields

The following fields must be present on the physical or digital invoice template itself, established during the authorization process with the SAR:

Taxpayer's legal name (razon social). The registered name exactly as it appears in SAR records.
RTN (Registro Tributario Nacional). The issuer's 14-digit tax identification number.
Commercial name (nombre comercial). The trade name under which the business operates, if different from the razon social.
Physical address. The fiscal domicile of the issuing establishment.
CAI code. The unique authorization number assigned by the SAR for that specific invoice range.
Authorized invoice number range. The starting and ending numbers of the batch approved under the assigned CAI.
Fecha limite de emision. The expiration date after which invoices bearing that CAI are no longer valid.
16-digit invoice number. A structured sequential number that uniquely identifies each document within the authorized range.

Every one of these elements is locked in place before the first invoice in a batch is ever used. If any field is missing or incorrect, the document fails compliance at the most basic level.

Fields Completed at Issuance

When a transaction occurs, the seller fills in the remaining required data:

Date of issue. The calendar date the invoice is generated.
Buyer identification. Name and RTN of the purchaser (subject to the threshold rule below).
Description of goods or services. A clear, itemized list of what was sold.
Unit prices. The price per unit for each line item.
Quantities. The number of units sold per line item.
ISV tax breakdown. The Impuesto Sobre Ventas amount calculated and displayed separately by applicable rate.
Total amount. The final sum including all taxes.

The Buyer Information Threshold Rule

Not every invoice requires full buyer details. Honduras applies a monetary threshold that determines how much customer data you need to capture:

Sales under L 10,000 (Honduran lempiras): The invoice may list the buyer simply as "Consumidor Final" (Final Consumer). No RTN or additional identification is required.
Sales of L 10,000 or above: Full customer identification is mandatory, including the buyer's name and RTN. Omitting this data on high-value invoices is a compliance violation.

For AP teams verifying inbound invoices, this threshold is a practical checkpoint. If the invoice total reaches L 10,000 or more and the buyer field reads "Consumidor Final," the document does not meet SAR requirements.

Understanding the Honduras RTN on Invoices

The RTN (Registro Tributario Nacional) is the universal taxpayer identifier in Honduras and appears on every compliant invoice, both as a pre-printed field for the issuer and as a required field for the buyer on transactions meeting the threshold.

The Honduras RTN invoice format follows a fixed 14-digit structure:

Digits	Meaning
1-2	Tax ID type indicator
3-4	Province code (departamento)
5-14	Unique identification number

The first two digits signal what kind of tax identity the number represents. Digits three and four correspond to the Honduran province where the taxpayer is registered. The remaining ten digits form the unique identifier assigned to that specific individual or entity.

Because the RTN links every taxpayer to their invoicing obligations, SAR cross-references it during audits and tax filings. An incorrect or missing RTN on an invoice can trigger rejection during fiscal reviews, making it one of the most critical Honduras invoice mandatory fields to verify on every document you process.

Autoimpresor vs Imprenta: Two Invoicing Modalities

Honduras recognizes two distinct paths for issuing fiscal documents, and understanding which one produced a given invoice matters when you are validating documents from Honduran suppliers. The two modalities are autoimpresor (self-printer) and imprenta (certified printing company). Both require CAI authorization from SAR, but the registration process, the day-to-day workflow, and the resulting invoice format differ significantly.

Autoimpresor (Self-Printer)

Under the autoimpresor modality, the taxpayer generates and prints fiscal documents directly from a registered digital system. This category covers two types of setups:

Computerized invoicing systems (Sistema de Facturacion Computarizado, or SFC), where the business uses software that meets SAR's technical specifications to produce invoices on demand.
Authorized cash register machines that are registered with SAR and configured to print fiscal documents with all mandatory fields.

Registering as an autoimpresor requires the taxpayer to file two forms with SAR:

SAR-926 (Declaracion Jurada): a sworn declaration confirming the taxpayer's intent and eligibility to self-print fiscal documents.
SAR-927: the formal self-printer registration that enrolls the specific system or equipment the business will use.

SAR evaluates whether the taxpayer's system complies with its technical requirements before granting authorization. Once approved, the business can generate invoices as needed, each one carrying the assigned CAI and following the authorized numbering sequence.

Imprenta (Certified Printing Company)

Under the imprenta modality, a third-party printing company produces pre-printed invoice forms on behalf of the taxpayer. The taxpayer then fills in the variable transaction details (buyer information, line items, amounts) by hand or with a simple stamp system.

The printing company itself must be registered in SAR's Registro Fiscal de Imprentas (Fiscal Registry of Printers). Only printers listed in this registry may produce fiscal documents. The authorization process for this modality involves two forms:

SAR-924: initiates the printer's enrollment in the Fiscal Registry of Printers.
SAR-925: authorizes the specific print run of fiscal documents for a given taxpayer.

When a taxpayer orders invoices through an imprenta, the printer is required to verify the taxpayer's identity by checking their national identity card (tarjeta de identidad) and RTN before producing any fiscal documents. Upon delivery, the printer must activate the fiscal documents, which links the printed batch to the taxpayer's CAI authorization in SAR's records.

What the Invoices Look Like

An autoimpresor invoice is typically a clean, software-generated printout with consistent formatting. An imprenta invoice is a pre-printed form with handwritten or stamped variable data, often on multi-part carbonless paper. Both are equally valid for tax purposes, provided the supplier holds a current CAI and the invoice contains all mandatory fields.

ISV Tax Treatment on Honduras Invoices

Getting the ISV (Impuesto Sobre Ventas) calculation wrong on a Honduras invoice is one of the most common compliance errors, and the rate structure makes it easy to see why.

ISV Rate Structure

Honduras applies two ISV rates:

15% standard rate on the majority of goods and services.
18% rate on designated luxury items, most notably alcoholic beverages, tobacco products, and certain other goods classified as non-essential.

Every taxable line item on an invoice must reflect the correct rate. Applying the standard 15% to a product that falls under the 18% luxury classification, or vice versa, constitutes a fiscal error that can trigger penalties during a SAR audit.

The Exemption Challenge: 270+ Product Categories

Over 270 categories of essential products are fully exempt from ISV under Honduran tax law. These span a wide range of sectors:

Basic grains and staple foods (rice, beans, corn, and similar items)
Pharmaceuticals and medical supplies
School supplies and educational materials
Books and printed publications
Petroleum products (fuel, diesel, and related derivatives)
Agricultural machinery and equipment

This extensive exemption list creates genuine classification complexity. A business selling mixed product lines must correctly categorize each individual line item to determine whether it is taxable at 15%, taxable at 18%, or fully exempt. Misclassification is one of the most common ISV compliance failures, particularly for companies with large product catalogs or those unfamiliar with the specific Honduran exemption schedule. The complete exemption list is codified in the Ley del Impuesto Sobre Ventas and its regulatory annexes, available through SAR's portal in Spanish.

Exempt vs. Exonerated: A Critical Distinction

Honduran invoices require a three-way tax classification that trips up many foreign finance teams:

Exempt (exento): Goods and services that the ISV law permanently excludes from taxation. These are the 270+ product categories written into the statute. No ISV is ever charged, regardless of the buyer or seller.
Exonerated (exonerado): Operations where ISV would normally apply but has been waived through a specific government dispensation. Exonerations are typically tied to special economic regimes, free trade zones, diplomatic privileges, or targeted government incentive programs. They require supporting documentation, such as an exoneration order, and are granted to particular entities rather than to product categories.
Taxable (gravado): All remaining operations subject to ISV at either the 15% or 18% rate.

The distinction matters on every invoice. Treating an exonerated sale as exempt, or failing to distinguish between the two, misrepresents the tax basis of the transaction and can invalidate the document for fiscal purposes.

ISV Presentation Requirements on Invoices

Honduras ISV tax on invoices must follow strict formatting rules. The ISV amount cannot be embedded in the unit price; it must appear as a separate, clearly identified line item. Beyond that, every invoice must break down its totals into distinct subtotals for each tax category:

Subtotal of exempt operations
Subtotal of exonerated operations
Subtotal of taxable operations (further separated by rate if both 15% and 18% items appear)
ISV amount calculated on the taxable subtotal
Grand total

This three-way subtotal structure on a single invoice is where errors concentrate. Invoices that lump exempt and exonerated amounts into a single non-taxed subtotal, or that fail to separate the ISV as its own line, risk rejection by the SAR and may not be accepted as valid fiscal support by the buyer's accounting department.

Monthly Filing Obligation

Businesses registered for ISV must file monthly returns through the SAR's online portal. The deadline is the 10th of the month following the reporting period. These returns reconcile the ISV collected on sales against the ISV paid on qualifying purchases, with the net amount due to the treasury. Late filing carries automatic surcharges and interest, making accurate and timely invoice records a prerequisite for meeting the monthly deadline.

Fiscal Document Types in Honduras

Honduras's invoicing framework defines eight distinct fiscal document types, each serving a specific transactional purpose. Every document type requires its own CAI authorization and follows the same 16-digit sequential numbering format. The two-digit document type code embedded in the numbering structure is what distinguishes one category from another.

Factura (Standard Invoice) is the primary fiscal document in the Honduran system and the one most finance professionals will encounter. A properly issued factura supports ISV tax credit claims for the buyer and qualifies as a deductible expense for ISR (income tax) purposes. If your organization purchases goods or services from a Honduran supplier, this is the document you need to validate for both tax credit recovery and expense recognition.

Ticket (Fiscal Voucher) serves a narrower function. It is issued exclusively for final consumer sales through authorized cash register machines. Because tickets are designed for retail point-of-sale transactions, they do not support tax credit claims. If a Honduran supplier issues you a ticket instead of a factura, you lose the ISV credit on that transaction — worth flagging in your vendor payment procedures.

Nota de Credito (Credit Note) is the corrective instrument used to annul operations, process merchandise returns, and apply discounts granted after the original invoice was issued. Each credit note must reference the original invoice it modifies, including the original CAI and document number.

Nota de Debito (Debit Note) handles the opposite scenario. It is issued for account adjustments that increase the amount owed by the buyer, such as additional charges, interest, or price corrections upward.

Guia de Remision (Remittance Guide) accompanies the physical transfer of goods within Honduran national territory and covers warehouse inventory movements. This is not a billing document. It does not generate tax obligations on its own but must travel with the merchandise to prove lawful transit.

Comprobante de Retencion (Withholding Certificate) must be issued at the exact moment of payment when withholding tax applies. If your company withholds ISV or ISR from a Honduran vendor payment, you are legally required to provide this certificate to the payee as proof of the amounts retained.

Constancia for Retenciones, Exentos y Exonerados y Casos Especiales provides formal documentation for withholdings, exempt transactions, exonerated operations, and other special cases that fall outside standard invoicing scenarios.

Orden de Compra Exenta (Exempt Purchase Order) applies specifically to exporters acquiring taxable raw materials or production inputs. This document allows qualifying exporters to purchase goods without ISV being charged, provided the inputs are destined for export production.

Understanding which document type applies to each transaction is essential for accurate tax reporting. Other Latin American countries maintain their own classification systems with different rules. Finance teams processing invoices across multiple jurisdictions may find it useful to compare Honduras's framework with, for example, Argentina's Monotributo invoice requirements and simplified tax regime, where invoice categories vary based on the taxpayer's registration regime rather than the transaction type.

From CAI to CAEE: Honduras's E-Invoicing Transition

Honduras is shifting from its paper-based CAI authorization model to a real-time electronic clearance system built around the CAEE (Codigo de Autorizacion de Emision Electronica). Under the CAEE model, SAR must authorize each electronic invoice before it reaches the recipient. Invoices are issued in XML format according to SAR's technical specifications, replacing the pre-printed correlative ranges that define the current CAI workflow. The trajectory follows a pattern now familiar across Latin America: moving from pre-authorization codes to real-time clearance, with the tax authority validating every document at the point of issuance.

Rollout Timeline and Taxpayer Scope

SAR is phasing in the e-invoicing mandate progressively. Large taxpayers face mandatory adoption first, with subsequent waves extending the requirement by sector, business size, and transaction volume. As of 2026, the full 100% e-invoice mandate has not yet been completed. Businesses currently operating under the CAI system should monitor SAR communications for their taxpayer category's transition date, since compliance timelines will vary based on where each entity falls in the rollout schedule.

Firma Electronica Avanzada

A critical prerequisite for e-invoicing is the Firma Electronica Avanzada (Advanced Electronic Signature), which SAR launched in March 2025 under Decree 149-2013, Honduras's Law on Electronic Signatures. Each certificate is valid for three years. SAR established tiered pricing to encourage broad adoption:

Public sector entities: free
Private sector taxpayers: L350 to L1,500, scaled by business size

Without a valid advanced electronic signature, taxpayers cannot authenticate electronic invoices under the CAEE model. This makes early registration a practical priority for businesses anticipating their inclusion in upcoming mandate phases.

Platform Infrastructure: SIISAR and Oficina Virtual

Two platform developments underpin the transition. The SIISAR (Sistema Integrado de Informacion del SAR) is a new integrated information system developed by gtt with support from the Inter-American Development Bank (IDB). Currently in its testing and validation phase, SIISAR will serve as the backbone for Honduras's electronic invoicing infrastructure.

On the operational side, SAR's Oficina Virtual replaced the legacy DET (Declaracion Electronica de Tributos) system as of June 3, 2024. According to the Inter-American Center of Tax Administrations (CIAT), 97 percent of the services provided by SAR are now available on the digital platform, reflecting the tax authority's broader commitment to modernizing tax administration and compliance processes.

SAR is also receiving technical assistance through the CIAT-SECO Cooperation Program for the electronic document rollout.

What This Means for Current CAI Users

Businesses that comply with today's CAI requirements will eventually need to transition to electronic formats once the mandate reaches their taxpayer category. The core compliance logic remains the same — SAR authorization before issuance — but the mechanism shifts from printed authorization codes and correlative ranges to real-time digital clearance. Preparing now by obtaining a Firma Electronica Avanzada and monitoring SIISAR developments positions your organization to meet the requirement without disruption when your transition window arrives.

Record-Keeping Requirements and Compliance Deadlines

Honduras requires all invoices and supporting fiscal documents to be retained for a minimum of five years from the date of issuance. This applies to every document type within the Regimen de Facturacion: standard invoices, credit and debit notes, purchase settlement receipts, and any other fiscal document bearing a CAI or CAEE authorization number. Both the issuer and the recipient share this obligation.

All accounting books and records must be maintained in Spanish, using either SAR-authorized software or officially registered ledger systems. Foreign companies operating in Honduras or processing Honduran invoices should ensure that any translated copies do not replace the Spanish-language originals. SAR treats the Spanish version as the legally binding record in any audit proceeding.

During the retention period, both physical and electronic records must remain accessible for SAR inspection upon request. If you store invoices digitally, the files must be retrievable in their original format with all mandatory fields intact. Physical copies, where applicable, must be legible and stored in conditions that prevent deterioration. SAR auditors can request access to either format at any point within the statutory window.

The statute of limitations for tax assessment varies depending on the taxpayer's filing status:

4 years for customs-related matters, covering duties and import taxes documented on fiscal receipts.
5 years for registered taxpayers who have filed their returns. SAR can audit and reassess tax liabilities based on invoice records throughout this period.
7 years for unregistered taxpayers or those who have failed to file required returns. This extended window reflects the higher enforcement priority SAR places on non-compliant entities.

These timelines run from the end of the fiscal year in which the tax obligation arose. For compliance planning purposes, the practical effect is straightforward: if you are a registered taxpayer filing on time, your invoice records must survive at least five years of potential SAR scrutiny. If there is any gap in your filing history, that window extends to seven years, making consistent record-keeping even more critical.