Modelo 303: file your VAT in 30 seconds.
Forget downloading the BOE file and uploading it to the tax office by hand. Cofactu aggregates the quarter's boxes from your invoices and expenses, signs with your certificate, and files directly with the AEAT. Response CSV saved in your audit trail.
Official BOE file signed and submitted · Confirmation CSV stored in the audit log
Frequency
Quarterly
Q1: Apr 1-20 · Q2: Jul 1-20 · Q3: Oct 1-20 · Q4: Jan 1-30 of the following year
AEAT method
Fichero AEAT BOE
Cofactu generates the official BOE file, signs it with your FNMT certificate, and submits it. You get a confirmation CSV.
Time with Cofactu
≈ 30 seconds
vs. 5-10 min downloading and uploading manually to the AEAT portal.
Who has to file Modelo 303?
- Self-employed and businesses under the General VAT Regime
- Taxpayers making supplies of goods or services subject to VAT
- Professionals with activity subject to VAT (not exempt)
- Landlords renting out property subject to VAT (commercial premises, offices)
The main boxes of Modelo 303
Cofactu fills them in automatically from your invoices, expenses, payroll, or rental income. It shows them in an editable preview before filing — you never submit without reviewing.
| Box | Name | What it covers |
|---|---|---|
| 01-09 | Output VAT, general regime | Taxable base and VAT output at 21%, 10% and 4% on domestic transactions. Auto-aggregated from your issued invoices for the quarter. |
| 28-29 | Deductible VAT, current domestic transactions | Base and input VAT on current purchases (expenses, utilities, services). Cofactu aggregates it from your quarter's expenses. |
| 30-31 | Deductible VAT, capital goods | Input VAT on fixed assets (equipment, furniture, business vehicles). Kept separate from current expenses so the deduction is correctly classified. |
| 36-39 | Deductible VAT, intra-community acquisitions | Base and VAT on intra-community acquisitions of goods and services. Cofactu reconciles it with the Modelo 349 codes (E/A/S/I). |
| 46 | Credit carried forward from prior periods | If VAT was refundable or carried forward in prior quarters, Cofactu carries the balance forward automatically. |
| 71 | Settlement result | VAT payable (positive) or refundable/to carry forward (negative). Calculated as output VAT minus deductible VAT minus prior carried-forward credit. |
| 76 | State share (percentage) | Percentage of the result attributed to the State administration. 100% by default unless a regional (foral) regime applies. |
| 78 | Regional community share (percentage) | Percentage attributed to the Basque Country or Navarre when the regional (foral) regime applies. Cofactu covers the Common Regime; the foral regime is not yet supported. |
What Cofactu covers today for this model
Covered
- General Regime with no equivalence surcharge or REBU/REA (covers ≈90% of small businesses and self-employed)
- Domestic transactions at 21% / 10% / 4% (all standard VAT rates)
- Intra-community acquisitions of goods and services (reconciled with 349)
- Capital goods (automatic current vs. investment classification)
- Offsetting negative balances from prior quarters
- General State Regime (100%)
Not yet covered
- Equivalence surcharge (retail trade)
- Special Regime for Used Goods (REBU) and Special Regime for Travel Agencies (REA)
- Regional (foral) regime (Basque Country, Navarre) — Cofactu covers the Common Regime
We expand coverage sprint by sprint. If a specific case is blocking you, write to us at hola@cofactu.com.
Common errors when filing this model
Cofactu validates these cases before submission and explains them with human-readable feedback before generating the file. If AEAT rejects it, we tell you exactly which box to check.
- 1xxx — Authentication errors (expired certificate, no AEAT permissions, NIF not registered in sandbox)
- 4001 — Invalid NIF or not found in the AEAT registry
- 4002 — Inconsistent amounts between boxes (e.g. output VAT doesn't match the taxable bases)
- 5xxx — Format errors in the BOE file (misplaced record, incorrect encoding)
- Output VAT vs. records mismatch — the sum of boxes 01-09 must match your Issued Invoices Register for the quarter
If you file Modelo 303, you probably also file
Models that typically go together for tax purposes — Cofactu aggregates the data between them automatically.
Modelo 130
IRPF installment payment
See guide
Modelo 111
IRPF withholdings
See guide
Modelo 347
Transactions with third parties
See guide
See the full summary of the 7 AEAT models Cofactu covers.
Frequently asked questions
Does Cofactu file it directly, or just download the file?
What happens if the AEAT rejects my 303?
Do I need a digital certificate?
Where does Cofactu pull the box values from?
What if I have the equivalence surcharge or REBU?
What about the refund at year end?
What if I file late?
File your Modelo 303 from Cofactu
The Free plan includes full VeriFactu invoicing. To file with AEAT from the app you need the Pro plan or higher. No lock-in.