How to issue an invoice with a CAI in Honduras

By the PymesPros team · Updated on October 20, 2026

What the CAI is

The CAI is the key the SAR gives a taxpayer so that they can invoice. It has 32 characters (letters and numbers) and is written in groups separated by hyphens to make it readable. Each CAI comes with two limits that matter as much as the key itself:

• The authorized range: from which number to which number you can invoice.
• The issue deadline: after that date the CAI no longer covers any document, even if you have numbers left.

Issuing outside the range or after the deadline has serious consequences: those documents cannot support a tax credit, neither for the person who issues them nor for the person who receives them.

How an invoice is numbered

The number has four blocks separated by hyphens, for example 000-001-01-00000001:

The document type code (invoice, credit note, debit note, receipt) is not made up: it comes from the resolution the SAR gave you for that range.

What your invoice must include

• Name and RTN (tax ID) of the issuer.
• Name and RTN or national ID number of the buyer.
• The CAI.
• The authorized range and the issue deadline.
• The full sequential number.
• The issue date.
• The detail: description, quantity and price of each line.
• Amounts separated by treatment: exempt, exonerated and taxable, with the ISV (sales tax) of each.
• The total, also in words.
• An indication of who each copy belongs to: the original is for the customer and the copy for the taxpayer.

Step by step to issue without mistakes

1. Register your CAI with its range and its deadline before issuing the first invoice.
2. Issue the invoice with the next number in the range. Sequential numbers go in order, with no gaps.
3. Give the original to the customer and keep the copy.
4. If you make a mistake, void the document. Do not delete it: the number stays used, with its reason, and you issue a new one.
5. Watch the range and the date. Request the next CAI in time: the SAR does not answer the same day, and running out of numbering means being unable to invoice.
6. When you close the month, the invoices issued are the basis of your ISV return.

A missing number without an explanation is the first thing a review questions. That is why an invoice is never deleted and its number is never reused: it is voided.

The most common mistakes

• Continuing to invoice with an expired CAI.
• Going past the last authorized number.
• Skipping numbers or deleting wrong invoices.
• Leaving the buyer without an RTN or with an incomplete name.
• Finding out too late that the range is almost used up.
• Mixing documents of different types in the same range.

How PymesPros helps

PymesPros controls your range and the CAI deadline, warns you when few documents or few days are left, numbers without gaps and does not allow deletion: only voiding, without reusing the number. Each invoice generates its accounting entry and its ISV without retyping, and it can carry a QR code so your customer can verify the document.

This guide is informational and does not replace the advice of a licensed public accountant. Rates, ceilings and dates are adjusted by the authorities from time to time: confirm them at the official source before applying them.

Frequently asked questions