Wrong numbering, incorrect VAT, misapplied withholdings and other mistakes that can cost you money. A practical guide to avoiding them.
If you are a freelancer in Spain, invoicing is part of your daily routine. But invoicing is not simply putting an amount on a document — there are regulations behind it that require specific data, fixed deadlines and mandatory formats. Getting it wrong can mean your client cannot deduct VAT, the Tax Agency penalises you or you lose money without realising it. This article reviews the most common mistakes and how to avoid each one.
Invoice numbering must be sequential within each series, with no gaps or repetitions. This is required by article 6.1 of RD 1619/2012. The most frequent errors are skipping numbers, repeating them, restarting the sequence mid-year or mixing numbering between series. Freelancers who invoice with Excel or templates end up with gaps because they delete invoices and do not reassign the number.
Use invoicing software that manages numbering automatically. If you use multiple series, each must have its own sequence. Do not restart numbering during the fiscal year and never delete an issued invoice to reuse its number — if there is an error, issue a corrective invoice.
Spain has three current VAT rates — 21% (standard), 10% (reduced) and 4% (super-reduced). Applying the wrong rate is common, especially when similar services are taxed at different rates. If you apply a lower rate, you pay less VAT than owed to the Tax Agency. If you apply a higher rate, your client overpays and will declare incorrect input VAT. In both cases, an inspection can lead to penalties and corrective invoices.
Check articles 90 and 91 of VAT Law 37/1992 to verify which rate applies to your activity. If in doubt, consult a tax advisor. Good invoicing software lets you configure VAT rates per product or service so the correct rate is applied automatically.
Article 6 of RD 1619/2012 defines which data every full invoice must contain. The most commonly forgotten are the recipient's NIF, their tax address, a detailed description of the services and the VAT breakdown separating the taxable base, rate and amount. An incomplete invoice may be rejected by your client, and the Tax Agency may consider it invalid — preventing the recipient from deducting input VAT.
Use a template or software that includes all mandatory fields and prevents you from issuing without completing them. Before sending each invoice, verify it shows your name and NIF, the recipient's full details, the sequential number, the date, the description, the taxable base, the VAT rate, the VAT amount and the total.
The factura simplificada has amount limits that many freelancers confuse. The general rule is that you can only issue one when the total does not exceed 400 euros VAT included. The 3,000-euro threshold only applies to specific activities listed in article 4.2 of RD 1619/2012 — hospitality, retail, passenger transport, hairdressers and other specific cases. If you are a consultant, designer or lawyer, your limit is 400 euros.
Check whether your activity is on the article 4.2 list. If it is not, your limit is 400 euros. When in doubt, always issue a full invoice — it meets all requirements and avoids problems. Remember that some operations prohibit the factura simplificada regardless of the amount, such as intra-Community supplies or reverse-charge operations.
IRPF withholding is only applied by professional freelancers (IAE sections 2 and 3) when invoicing other businesses or professionals. The standard rate is 15%, reduced to 7% for new freelancers. The most common errors are business freelancers applying withholding when they should not, professionals failing to apply it when invoicing companies, withholding being applied when invoicing individuals (it never applies) or using the 7% rate beyond the reduced period.
First, determine whether you are a professional or business freelancer based on your IAE heading. If you are a professional invoicing a company, apply withholding. If invoicing an individual, do not. If you are a business freelancer, never apply withholding. Configure your software to handle withholding automatically based on the recipient type.
Quarterly VAT returns (modelo 303) and IRPF instalment payments (modelo 130) have fixed deadlines — 1-20 April, 1-20 July, 1-20 October and 1-30 January. Filing late triggers a surcharge of 1% plus an additional 1% for each full month of delay during the first twelve months, and 15% plus late-payment interest from the twelfth month onwards. If you had no invoices during the quarter, you must still file modelo 303 marked as "no activity".
Mark the deadlines in your calendar on the first day of each year. If your invoicing software generates quarterly summaries, use them to prepare returns in advance. Do not leave data gathering for the last day — a well-organised quarter can be filed in minutes.
From 1 July 2027, all freelancers must use software compliant with RD 1007/2023. This means generating tamper-proof records with SHA-256 hashes, chaining records, including QR codes on invoices and, in the recommended mode, automatically submitting records to AEAT. Spreadsheets, templates and manual invoicing will no longer be valid. Penalties for non-compliance can reach 50,000 euros per fiscal year.
Do not wait until the deadline approaches. Migrating an invoicing system involves reviewing your tax configuration, importing data and learning the new tool. Start using compliant software now — so that when July 2027 arrives, you just keep invoicing as usual.
CokuApp handles your business invoicing in full compliance with Spanish tax regulations, including Verifactu. Fewer mistakes, fewer worries.