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Modelo 303 for Q2 2026: The Checklist to Review Before Filing Your Quarterly VAT

If you run a business in Spain — an agency, a property management firm, a gestoría, or you're self-employed — the second-quarter *Modelo 303* is one of the July jobs you can't push back. It's the quarterly VAT self-assessment: you declare the VAT you charged clients (output VAT), subtract the deductible VAT you paid on your expenses (input VAT), and settle the difference with the tax authority (AEAT).

Most mistakes on the 303 don't come from the form itself. They come from what feeds it: a missing supplier invoice, the wrong VAT rate on a line, an expense that isn't actually deductible. This checklist is built to catch those before you hit submit — not after AEAT does.

First, lock in the dates

The Q2 return covers April, May and June 2026. The filing window is 1 to 20 July 2026. Because 20 July falls on a Monday this year, there's no extension to the next business day.

Two dates matter depending on how you pay:

Direct debit (domiciliación): you must file by 15 July 2026. AEAT charges your account on 20 July.
Any other payment method (or a nil / offset return): you have until 20 July 2026.

Miss the window and you're looking at surcharges for late filing, so put the earlier date in your calendar if you plan to direct-debit.

The checklist

1. Reconcile your issued invoices (output VAT)

Every sales invoice dated April–June must be in the return. Confirm the count matches your invoicing system, check for gaps in the numbering, and make sure credit notes (facturas rectificativas) are included with the right sign.

For each line, verify the taxable base and the rate. Spain has three VAT rates — 21% general, 10% reduced, and 4% super-reduced — and applying the wrong one is one of the most common and most visible errors.

2. Reconcile your received invoices (input VAT)

This is where money is usually left on the table. You can only deduct VAT that is backed by a complete invoice (a simplified ticket without your tax details generally doesn't qualify), tied to your business activity, and booked in the right quarter.

Go through your expenses and confirm:

You have the actual invoice, not just a card receipt or a bank line.
The supplier's tax ID (NIF/CIF) and your details are on it.
The expense is genuinely deductible — no fully personal costs slipping in.
The VAT amount and base are captured exactly as printed, not rounded or retyped by hand.

Manual data entry from a stack of supplier invoices is where errors and lost hours concentrate. If you're still keying these in one by one, automating invoice extraction over WhatsApp pulls the supplier, base, rate and VAT amount into a structured sheet in seconds — which is exactly the data a 303 reconciliation needs.

3. Check special VAT regimes and cross-border lines

Run through anything that isn't a plain domestic sale:

Intra-community transactions: you need a valid VAT number registered in VIES/ROI, and these go in their own boxes.
Reverse charge (inversión del sujeto pasivo): confirm which operations shift the VAT liability to you.
Equivalence surcharge (recargo de equivalencia) if you sell to retailers under that regime.
Pro rata if you have both taxable and exempt activity.

4. Carry forward any balance to offset

If a previous quarter closed with VAT in your favour that you chose to offset (cuotas a compensar), make sure that amount is carried into the correct box of this return. It's easy to forget and effectively hand money to AEAT.

5. Cross-check against your other July forms

The 303 isn't filed in isolation. The same period also drives Modelos 111, 115, 130 and 131, among others. The revenue and expense figures should be internally coherent across them — a sales total that contradicts your income-tax instalment (Modelo 130) is a red flag AEAT can see too.

6. Mind the new 2026 changes to the form

For 2026, Order HAC/27/2026 updated Modelos 303, 322, 353 and 390. The visible change for most filers is a new box [112] for a fuel-related payment on account (petrol, diesel and biofuels leaving the non-customs warehouse regime), which is subtracted when calculating the result. These changes apply for the first time to the Q2 2026 self-assessment. Most SMBs won't touch box 112, but it's worth knowing why the form looks different this quarter.

7. Decide the result and how you'll file

Your 303 closes as to pay, to offset, or to refund. Note that a straight refund request (devolución) is generally only available in the fourth-quarter return unless you're registered in the monthly refund register (REDEME). For Q2, a favourable balance normally carries forward to offset.

Found a mistake in a past quarter? Use the rectificativa

If your reconciliation surfaces an error in an *earlier* period, the fix is now built into the form. For periods from the third quarter of 2024 onward, you correct them with a rectifying self-assessment (autoliquidación rectificativa): you file a new Modelo 303, tick the "autoliquidación rectificativa" box, and reference the receipt number of the original return. This replaces the old split between complementary returns and formal correction requests for most cases.

And Verifactu? Not for this filing

There's been a lot of noise about Verifactu, the verifiable-invoicing system. For the Q2 2026 return it does not apply: the obligation was deferred to 1 January 2027 for companies subject to corporate income tax and 1 July 2027 for the self-employed. You don't need Verifactu-compliant software to file this quarter — but it's a good moment to make sure your invoicing and data capture are clean and structured, because that's what the transition will reward.

Where the time actually goes

A clean 303 is really a clean set of invoices. The form takes minutes; gathering, reading and typing the underlying documents is what eats an afternoon. Moving that capture off manual entry — turning PDFs and photos of invoices into a ready-to-use Excel — is the single change that makes every future quarter faster and less error-prone. If you're weighing your options, this breakdown of WhappScan vs manual entry vs traditional OCR covers the trade-offs.

WhappScan turns invoices sent over WhatsApp into structured data (Excel or API) in seconds, so your VAT reconciliation starts from clean numbers instead of a pile of paper — try it at whappscan.com.