Invoicing in a Foreign Currency in Oman

An Oman e-invoice can be issued in a currency other than the rial, but it must then say three more things: that OMR is the VAT accounting currency, what the exchange rate is, and what the VAT comes to in rials. Leave one out and the rules reject the invoice. If the invoice is in rials, the opposite applies and the exchange rate must be absent.

This page walks through the fields and the rules behind them, with a worked example. It assumes a seller invoicing in US dollars. The same fields apply to any non-OMR currency.

What does Oman require when an invoice is not in rials?

Three things, each with its own rule. All three are fatal: a document that fails one is refused.

The three together describe one idea. The invoice is priced in dollars, the VAT is declared in rials, and the rate is the bridge between them.

A fourth rule keeps the bridge honest. IBR-059-OM fixes its direction: the source currency is the invoice currency and the target is the VAT accounting currency. A rate written the wrong way round is a different number, so the pack states which way it runs.

What does IBR-172-OM check?

That a domestic invoice does not carry a rate. The pack text is: "If Invoice currency code (IBT-005) is "OMR" then Exchange Rate (BTOM-003) MUST NOT be present."

It is the mirror of IBR-004-OM. Together they enforce the rule in both directions. A common cause of failure is a billing system that adds a rate of 1 to every document whether it needs one or not. In an invoice in rials the field has to be removed, not left at one.

How is the invoice laid out?

The document currency, the tax currency and the rate are three separate elements, and the VAT total appears twice, once in each currency.

<cbc:DocumentCurrencyCode>USD</cbc:DocumentCurrencyCode>
<cbc:TaxCurrencyCode>OMR</cbc:TaxCurrencyCode>
<cac:TaxExchangeRate>
  <cbc:SourceCurrencyCode>USD</cbc:SourceCurrencyCode>
  <cbc:TargetCurrencyCode>OMR</cbc:TargetCurrencyCode>
  <cbc:CalculationRate>0.3850000</cbc:CalculationRate>
</cac:TaxExchangeRate>
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="USD">50.000</cbc:TaxAmount>
  ...
</cac:TaxTotal>
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="OMR">19.250</cbc:TaxAmount>
  ...
</cac:TaxTotal>

The rate in this example is an illustration of the layout, not a rate to use.

The second TaxTotal is the Oman group BG-OM-9. It also carries a breakdown by VAT category, BG-OM-10, and IBR-066-OM requires that breakdown whenever the invoice is not in rials and at least one category is S. IBR-136-OM requires every amount in that block to carry the VAT accounting currency as its currencyID.

A worked example

One line, 1,000.000 USD at the standard rate of 5%, and a rate of 0.3850000 OMR per USD:

IBR-065-OM is the check on the last row: the VAT in rials has to equal the rate multiplied by the VAT in dollars. A system that rounds the converted figure differently from the issuing system can produce a document that looks right and fails that equality, so compute the rial figure once and carry it, rather than recomputing it downstream.

The numbers are for illustration. Which rate your business applies is a separate question, and the last section addresses it.

How many decimal places can the rate and the amounts carry?

The amounts may carry up to three decimal places and the rate up to seven. The pack rule IBR-DEC-03-OM caps every amount at three decimals, including amounts in a currency that normally has two. A dollar invoice written to two places is within the limit, and an amount written to four is not.

The rate has its own rule, IBR-005-OM: up to seven decimal places when the VAT accounting currency is OMR and the invoice currency differs.

The data dictionary disagrees. Its BR-OM-5 says the rate should have at most four decimal places. The pack we run in production, from the 2026-Q2 final set, says seven. We build to the pack because the pack is what validates the file. The data dictionary article explains how the two relate.

The rial's three decimals are the more common source of trouble, and the general three-decimal rule and its line-level tolerance are covered in the format article.

Which exchange rate must I use?

The rules do not say. The packs require a rate, check its direction and its precision, and check that the VAT in rials equals the rate times the VAT in the invoice currency. They do not name a source, a date or a rounding convention, and neither does this page.

Which rate applies, and on which date, is a tax question. Ask your tax adviser, or the Oman Tax Authority directly. If you hold a rate in your ERP already, send that figure and make sure the same figure is used for the rial amounts.

Where is this handled in accounting software?

A cloud accounting system that invoices in several currencies already stores a rate per invoice, and the work is making sure it reaches the file. The Xero guide covers how that system carries it, including the rule that sends a USD invoice back for a missing rate: e-invoicing in Oman from Xero. To check any invoice before sending it, run it through validation: how to test an Oman e-invoice before you send it.

When the rejection comes back, why Oman e-invoices get rejected lists the rest by identifier.

What is not settled here

Which rate. See above. This page does not recommend one.

Gains and losses. Exchange differences between invoice date and payment date are an accounting matter and are not in the e-invoice rules.

Rule changes. The rule texts are from the 2026-Q2 final packs as we ship them today. The version history is tracked here.

What to do with this

If any of your Omani contracts are priced in dollars, find a recent invoice and check four things: the currency of the document, the VAT accounting currency, the rate with its direction, and the VAT in rials. If your system adds a default rate to rial invoices, that is the first thing to remove.

GoRoute takes the invoice currency and the rate as fields, builds the rial VAT block and checks the rules before sending. The Oman e-invoicing page sets out the service, the documentation has the field names, and the tutorials show a run. To go through your own invoices, book a demo.

GoRoute is accredited by the Oman Tax Authority on 29 July 2026 through Union Digital Technologies SPC, and is a certified Peppol Access Point (POP000991).

Primary sources: Oman Tax Authority — the authority that publishes the Oman e-invoicing rules; Peppol technical documentation — the PINT specification this profile extends.