When is my OSS VAT return due?

The Union OSS return is quarterly, and it's due by the end of the month after each calendar quarter: 30 April (for Jan–Mar), 31 July (Apr–Jun), 31 October (Jul–Sep), and 31 January (Oct–Dec). Unlike many national VAT returns, this deadline does not move to the next working day if it falls on a weekend or public holiday — file and pay on or before the date itself.

Do I have to file an OSS return if I made no cross-border sales that quarter?

Yes. Once you're registered for OSS you must submit a return for every quarter, even a 'nil return' with no sales to report. Skipping it counts as a missed return, and three consecutive missed (and reminded) returns can get you excluded from the scheme.

Which exchange rate do I use to convert non-euro sales for the OSS return?

Use the European Central Bank reference rate published on the last day of the tax period (the last day of the quarter). If the ECB published no rate that day — for example a weekend or holiday — use the rate published on the next day. This one rule applies even if your home country hasn't adopted the euro.

Can I deduct my input VAT (business expenses) on the OSS return?

No. The OSS return only declares the VAT you owe on your cross-border B2C sales — there is no box to offset VAT you paid on business expenses. You recover that input VAT separately: through the EU electronic VAT refund mechanism (Directive 2008/9/EC), the 13th Directive procedure, or your ordinary domestic VAT return if you're registered at home.

I made a mistake on a past OSS return — how do I fix it?

You don't amend the original return. Instead you correct it in a dedicated corrections section of a later quarterly return, broken down by the original period and the member state of consumption. Corrections can generally be made up to three years after the deadline of the return that was wrong.

How to file your first OSS VAT return: deadlines, nil returns, corrections

The short version

The Union OSS return is quarterly, filed through the same home-country portal you registered in. In it you list your cross-border B2C sales broken down by country of the customer and by VAT rate, and it tells you the total VAT to pay. You always file — even a quarter with zero sales needs a nil return — you convert any non-euro amounts at a fixed ECB rate, you cannot deduct your own business expenses on it, and you pay in one lump to your home tax authority by the same deadline.

This is a plain-language orientation aid, not tax advice, and it covers the Union scheme (an EU-established seller's normal OSS). See the disclaimer, and check your own tax authority's OSS portal or an accountant for the exact screens and any national specifics.

The quarterly rhythm and its deadlines

Union OSS runs on calendar quarters. Each return — and the matching payment — is due by the end of the month following the quarter it covers:

Tax period	Covers sales in	Return & payment due by
Q1	January – March	30 April
Q2	April – June	31 July
Q3	July – September	31 October
Q4	October – December	31 January (of the next year)

The OSS deadline does not move. With many national VAT returns, a due date on a Saturday, Sunday, or public holiday rolls to the next working day. OSS is stricter: the deadline is the date itself. If 31 January is a Sunday, you still file and pay by that Sunday. Build your reminders around the hard date.

What goes in the return

An OSS return doesn't ask for individual invoices. You report, for the whole quarter, your eligible cross-border B2C supplies grouped by:

Member state of consumption — the customer's country;
VAT rate applied — standard or, where the product qualifies, a reduced rate for that country (several countries have more than one rate, so a single country can appear on more than one line);
the total taxable value and the VAT amount for each of those country-and-rate lines.

The portal totals it up into a single figure of VAT due across all countries. This is exactly the data the threshold calculator and the worked examples get you thinking in — sales split by destination country — so if you've been tracking your sales that way already, the return is mostly a transcription job.

Nil returns: you file even with nothing to report

Once you're in the scheme, every quarter needs a return — there's no "skip it because I had a quiet quarter". A quarter with no OSS sales is filed as a nil return (all zeros). This matters beyond tidiness: missing returns is how sellers accidentally get thrown out of OSS. Three consecutive returns that are still missing after the reminders can trigger exclusion from OSS (and IOSS) — the same two-year lockout that page describes. A 30-second nil return avoids all of that.

Currency: one ECB rate for the whole quarter

If you sold in a currency other than the euro — Swedish krona, Polish złoty, Danish krone, and so on — you convert those amounts to euros for the return using the European Central Bank reference rate published on the last day of the tax period (the last day of the quarter). If the ECB published no rate that day (a weekend or holiday), use the rate published on the next day. You do not use the rate on each sale's date — it's one rate for the whole quarter, which keeps the arithmetic simple. This rule applies even if the country you registered in hasn't adopted the euro.

The gotcha: no input-VAT deduction on the OSS return

This surprises almost everyone who's used to a normal VAT return. On your domestic return you offset the VAT you owe against the VAT you paid on business expenses, and remit the difference. The OSS return has no such box. It is purely a declaration of the VAT you owe on your cross-border sales — you pay that in full.

You don't lose the input VAT; you just reclaim it through a different channel:

the EU electronic VAT refund mechanism (Directive 2008/9/EC) for VAT you were charged in another member state;
the 13th Directive procedure, in the relevant cases; or
your ordinary domestic VAT return, if you're VAT-registered at home, for the home-country portion.

Practical effect: budget to pay the OSS figure gross, and treat your input-VAT recovery as a separate, later process — don't expect to net it off inside OSS.

Fixing a mistake on a past return

You don't reopen or amend the original return. Instead, once a return period is closed, corrections to it are made in a dedicated corrections section of a later quarterly return, itemised by the original period and the member state of consumption affected. You can generally make such a correction up to three years after the deadline of the return that contained the error. So an under- or over-declaration from an earlier quarter gets trued up on your next filing, not by editing history.

Paying what you owe

You make one payment, for the whole return, to the tax authority of the country you registered in (your member state of identification) — not a separate payment to each customer country. That home authority then distributes the money to the other countries for you; that redistribution is the entire point of the One Stop Shop.

When you submit the return, the portal gives you a unique reference number for it (built from your country code, your VAT identification number, and the period). You must quote that reference on the payment so it's matched to the right return. Payment is due by the same deadline as the return (end of the month after the quarter) — and, like the filing deadline, it doesn't shift for weekends or holidays.

What to do right now

Not sure you even have to be in OSS yet? Check first — the €10,000 threshold calculator and the 6-question guide tell you whether you've crossed the line that makes OSS relevant at all.
Just realised you crossed a while ago? Registration can't be backdated freely — read registered late? before you file, so earlier sales are handled correctly.
Small overall but over €10,000? The SME exemption scheme may let you skip OSS returns entirely — worth checking before you commit to quarterly filing.
Ready to file? Pull your quarter's sales split by customer country and VAT rate, convert non-euro amounts at the quarter-end ECB rate, and enter them country by country — then pay the total, quoting the return's reference, by the deadline.

Open the €10,000 threshold calculator → · Do I even need OSS? (6-question guide)

Sources

Quarterly return, end-of-following-month deadline, nil returns, the corrections block, the unique payment reference, and payment to the member state of identification — European Commission, Directorate-General Taxation and Customs Union, "Declare and pay in OSS".
The deadline not shifting for weekends/holidays, and no input-VAT deduction on the OSS return (recover via the 2008/9/EC refund mechanism, the 13th Directive, or the domestic return) — Marosa VAT, "OSS VAT Returns: Filing, Deadlines & Payments"; Sovos, "OSS VAT Returns: Deadlines, Exclusions and Penalties".
Currency conversion using the ECB reference rate on the last day of the tax period (next day if none published) — European Union, Your Europe, "EU VAT One Stop Shop (OSS)"; German Federal Central Tax Office (BZSt), "One-Stop-Shop, non-Union scheme".
The three-consecutive-missed-returns exclusion this page links out to — covered on our own registered late? page, sourced there.

Disclaimer

This page and the calculator are a self-check aid, not tax advice. The mechanics above describe the Union OSS scheme in general terms; the exact portal screens, national payment details, and edge cases can differ by country and change over time. Verify your own situation against the EU Commission's One Stop Shop portal, your own tax authority's OSS guidance, or an accountant before you file.