Portuguese IT Freelancers Billing in USD or GBP: Accounting, VAT, and Withholding

It's the end of the month. You just sent an invoice to your client in San Francisco for $6,000. By the time it lands in your bank account, Wise has converted it, Revolut took a fee, and the amount on the bank statement is €5,412.38 — not the €5,498 you wrote on the invoice. Now your accountant wants to know which number goes into the IVA records.

If you're a Portuguese IT freelancer — developer, designer, DevOps, AI consultant — and most of your revenue comes from clients outside Portugal, the mechanics of billing in USD or GBP are where things get fiddly. The good news: once you understand three rules, it's mostly routine. The bad news: if you get any of the three wrong, you either overpay IVA, underpay IRS, or end up arguing with AT over numbers that don't match — our complete guide to invoice automation covers the processing side once invoices are in the right format.

Why This Is More Complex Than a Domestic Invoice

When you bill a client in Lisbon for €5,000, the numbers don't move. The invoice says €5,000, the bank receives €5,000, and your accounting records €5,000.

A foreign-currency invoice has three different "truths" for the same transaction:

1. The amount you invoiced in the foreign currency ($6,000 USD)
2. The euro amount on the invoice itself (converted at a specific rate on a specific date)
3. The euro amount that actually arrived in your bank, after FX and fees

Portuguese accounting wants all three reconciled. Your client's accounting wants something that matches what they paid. And AT wants the euro amount from the invoice to show up in your IVA records and IRS declaration — not the amount on the bank statement.

Rule 1: The Invoice Must Be Issued in Euros (Even if You Bill in USD)

This is the first thing most freelancers get wrong. Article 36 of the CIVA (IVA Code) requires Portuguese invoices to show the IVA amount in euros, even if the invoice total is in foreign currency.

In practice, this means your invoice should show both:

• Total in the contract currency (e.g., $6,000 USD or £4,500 GBP)
• Equivalent in euros, using a defined exchange rate, with the rate source and date explicitly stated

Most invoicing tools (including the free Portuguese billing portal Faturas do AT) handle this automatically — but only if you tell them which exchange rate to use. If you issue an invoice purely in USD with no euro equivalent, it's technically non-compliant, and any IVA calculation becomes ambiguous.

Rule 2: Use the Exchange Rate from the Invoice Date, Not the Payment Date

The CIVA specifies that the conversion rate for IVA purposes is either:

• The last exchange rate published by the European Central Bank (BCE) before the date of the taxable event
• Or the last rate published by the Bank of Portugal

Most accountants default to the BCE reference rate from the day the invoice was issued. That rate is what goes on the invoice, in the IVA records, and in your Modelo 3 at year-end.

The rate on the day the money arrives — 30 or 60 days later — is irrelevant for IVA purposes. What happens on payment day is a separate accounting entry: an FX gain or FX loss, which affects your IRS but not your IVA.

Practical example:

• April 1: You invoice a US client for $6,000. BCE rate is 1.0900 USD/EUR. The invoice shows $6,000 / €5,504.59.
• April 30: Wise deposits €5,412.38 in your Portuguese bank after conversion at 1.1080 and a small fee.
• IVA records: €5,504.59 (the invoice amount).
• IRS records: €5,504.59 revenue + €92.21 FX loss on collection.

If your accountant is putting €5,412.38 in your IVA records, that's wrong — and AT cross-references it.

Rule 3: Most B2B IT Services Outside Portugal Are "Localizadas Fora" — No Portuguese IVA

Here is where Portuguese IT freelancers actually save money, assuming they get the classification right.

For B2B services (your client is a business with a valid tax ID), the "place of supply" rules in Article 6 of the CIVA generally place the service where the client is established, not where you are. For most IT services — development, consulting, design, SaaS implementation — this means:

• Client in another EU country (e.g., Berlin, Dublin, Madrid): Service is located in that country. No Portuguese IVA. You note "IVA autoliquidação" / "reverse charge" on the invoice and the client self-assesses VAT. You must list the transaction in the Recapitulativa (VIES) declaration.
• Client outside the EU (e.g., US, UK post-Brexit, Brazil, Australia): Service is located outside the EU. Not subject to Portuguese IVA. You note "não sujeito a IVA — artigo 6.º n.º 6 do CIVA" or similar on the invoice.

For this to work cleanly, three things must be true:

1. Your client is a business, not a consumer (you should hold their VAT ID or equivalent registration).
2. The service is not one of the exceptions (e.g., real-estate-linked services, passenger transport, in-person events — none of which typically apply to IT freelancers).
3. Your invoice explicitly references the legal article exempting it. "No IVA, they're abroad" is not sufficient; AT wants the CIVA article cited.

If you're issuing invoices to US clients with 23% Portuguese IVA applied, you are overcharging them. They can't reclaim it. Most will quietly pay once, then find another supplier.

Where Foreign Withholding Shows Up (and What to Do About It)

Some countries deduct withholding tax from payments to foreign contractors. The mechanics vary a lot by country:

• US: Most B2B payments to Portuguese contractors are not subject to US withholding — provided you've submitted a W-8BEN form to the client. Without it, the client may withhold up to 30% by default. Send the W-8BEN before the first invoice, not after.
• UK: Generally no withholding on services paid to EU-resident suppliers with a valid tax ID. Your NIF plus invoice with Portuguese address is usually enough.
• Brazil, India, some LATAM markets: Withholding at source is common, often 10–15%. The treaty with Portugal may reduce it, but only if you provide a Residência Fiscal certificate (form 21-RFI or a certificate of tax residency issued by AT).

When withholding does happen, the money never arrives in your account — the client remits it to their own tax authority and sends you proof. For Portuguese IRS purposes:

• The gross invoice amount (in euros, at the invoice-date rate) is your revenue.
• The withheld amount is a foreign tax credit you can claim on your IRS return, subject to the relevant double-taxation treaty limit. You need the foreign withholding certificate as evidence.

Most freelancers discover this the first time it happens, panic, then realize it's recoverable — but only if they kept the documentation. Keep every withholding certificate. Give them to your accountant at year-end.

What AT Actually Checks

Three things, in order of how often they go wrong:

1. IVA records matching invoices. AT's system compares the euro amount on your invoices against what you declared in your monthly or quarterly IVA. If those numbers drift apart because you used the payment-date rate somewhere, you'll get a query.

2. Recapitulativa (VIES) declarations. Every B2B sale to an EU client under reverse charge must appear in your VIES declaration. Missing entries are the most common cause of EU tax authority letters — not from AT, but from the client's country.

3. Exchange rate source. On an audit, AT may ask which rate you used. "BCE reference rate on the invoice date" is the clean answer. "Whatever rate Google showed me" is not.

Practical Checklist for Every Foreign-Currency Invoice

Work through this list every time you send an invoice in USD, GBP, or any other non-euro currency:

1. Confirm the client's business status. Hold a copy of their tax registration or VAT ID. Individuals (B2C) have completely different rules — don't mix them up.
2. Pick the correct IVA treatment. EU business client → reverse charge, cite the CIVA article, include their VAT ID on the invoice. Non-EU business client → not subject to IVA, cite the article. Consumer client → different rules; talk to your accountant first.
3. Use the BCE reference rate from the invoice date. Screenshot the rate or use a tool that records it. Same rate goes on the invoice, in IVA records, and in your IRS.
4. Put both currencies on the invoice. Foreign-currency total, euro equivalent, exchange rate, rate date, rate source.
5. For US clients, send a W-8BEN before the first invoice. For treaty-country clients with withholding, send the Residência Fiscal certificate.
6. Keep every withholding certificate. No certificate, no foreign tax credit at year-end.
7. Record FX gain/loss at payment time. The delta between invoice-date euros and actual-received euros is a separate accounting entry — not a correction to the invoice.
8. File VIES on time. Monthly if you're over the threshold, quarterly otherwise. Don't skip it just because reverse-charge transactions "have no IVA."

Billing foreign clients in USD or GBP isn't harder than billing domestic clients — it's just different. The mechanics are stable once you've set them up. What trips freelancers up is treating the three euro amounts (invoice, payment, bank) as interchangeable. They aren't. Each has a specific role, and AT expects them in specific places.

If your invoicing tool already handles the BCE rate, the euro equivalent, and the reverse-charge legal text automatically, you're mostly done. If you're still doing it by hand in a Google Doc, you're one forgotten rate away from a mismatch that shows up six months later.

Build the habit of running the checklist above for each foreign invoice. Or automate the mechanical parts so the habit runs itself — see how Faturiza extracts invoice data into a structure your accountant can reconcile on the homepage, and check the poupança calculator if you want to see what the admin overhead of foreign invoicing actually costs you per month. If you work with a Portuguese accountant who still processes your foreign invoices by hand, point them to our accountant guide — the reconciliation is the same, just at 20× the volume.