Modelo 303: what it is, who files it, and how to fill it in step by step

The modelo 303 is the quarterly VAT self-assessment that every autónomo (self-employed worker) with VAT-liable activity has to file, and out of its sixty-plus boxes, most of them will never affect you. The real worry usually isn’t “what is it”, but what happens if you get something wrong: a wrong box is fixed with a supplementary return, and the sooner you file it, the less it costs — see what happens if you file late. And if the result comes out negative, that balance isn’t lost: it carries over to the next quarter, as we cover in VAT to offset from previous quarters.

This guide comes in two parts: first what the 303 is and who has to file it, and then, with a real example, box by box, so you can sit down in front of the Spanish Tax Agency (Agencia Tributaria) form and complete it without hesitation.

This guide covers the modelo 303, used in the common territory and (with deadline nuances) the Basque Country. If you pay tax in Navarre, your VAT form is the F-69, with its own boxes. In the “Before you open the form” section there’s a “Where do you pay tax?” selector summarising which form and deadlines apply to you; the boxes explained afterwards are those of the 303.

What form 303 is, and who files it

Form 303 is the quarterly VAT self-assessment. It tells the tax office two things: how much VAT you charged your clients (output VAT) and how much you paid your suppliers (input VAT). The difference is what you pay, or what stays in your favour.

Every self-employed person or company carrying out VAT-liable activities files it, even for a quarter with nothing in it: as long as you are registered, the return is due. With no activity you file it as a nil return, which is not the same as not filing.

One idea that saves a lot of grief: the VAT you charge is not yours. You collect it for the tax office and hand it back each quarter. Treat it as income for three months and the 20th hurts.

Is form 303 cumulative? No: each quarter stands on its own

This is the most repeated mix-up between the two quarterly forms a freelancer files, and you will find it written backwards more than once. It is worth getting straight, because it changes what you put on the form:

• Form 303 is not cumulative. Each self-assessment covers the operations of that settlement period (the quarter, or the month if you file monthly) and nothing else.¹ If the second quarter came out at €1,400 to pay, that figure does not reappear in the third: the third is worked out afresh, with the third quarter’s invoices only.
• Form 130 is cumulative, if you are taxed under the common territory: each quarter is calculated on your net income from the first day of the year to the last day of the quarter, and from that you subtract withholdings and the previous quarters’ payments.² It is set out in quarterly income tax, which also covers a twist: under the regional (foral) regimes the 130 is not cumulative either.

The only thing that travels from one quarter to the next on the 303 is the balance in your favour when the result comes out negative. And that is not the form accumulating: it is a pending amount you carry until you use it up, which is a different thing (VAT to offset from previous quarters explains it).

A practical rule so you don’t get it wrong: if you find yourself adding up invoices from months you already declared, on the 303 you have gone too far back; on the 130, you are on track.

The example we’re going to use

Marta is a freelance graphic designer. In the second quarter of the year she has issued three invoices to Spanish clients and received five invoices for deductible expenses.

Invoices issued (income):

Invoices received (deductible expenses):

With these figures we can already do the maths: 1,575 euros of output VAT (IVA repercutido) minus 174.30 euros of input VAT (IVA soportado) = 1,400.70 euros to pay. If you need to review exactly what input and output VAT are, it’s worth being clear on that before going on. If you want to run the quick calculation with your own figures, use the quarterly VAT calculator.

Now it’s time to transfer those numbers to the form.

Before you open the form

This guide follows the modelo 303 of the common territory. If you pay tax under a regional (foral) regime, the form and some deadlines change:

To file the modelo 303 you need to access the Agencia Tributaria’s electronic office with a digital certificate, electronic DNI or Cl@ve PIN. Once inside, look for “Modelo 303” in the VAT procedures section and select the relevant quarter.

The form will ask for your NIF (tax ID), name, tax year and period (1T, 2T, 3T or 4T). Fill in those identifying details and you’ll reach the body of the form, which is organised into three main blocks: output VAT, deductible VAT and result.

From here on it’s the box-by-box map: this is the part for when you already have the form in front of you. If you only wanted to know whether it applies to you and what happens if you get it wrong, everything above has you covered.

Block 1: output VAT (boxes 01 to 26)

This block gathers all the VAT you’ve charged your clients during the quarter. The Agencia Tributaria calls it “IVA devengado” (output VAT) or “régimen general” (general regime).

Boxes 01 to 09: operations by VAT rate

Here you declare your sales grouped by tax rate, and the rows run from the lowest rate to the highest, which is the opposite of what you would assume:³

• Boxes 01, 02, 03: operations at the super-reduced rate of 4%.
• Boxes 04, 05, 06: operations at the reduced rate of 10%.
• Boxes 07, 08, 09: operations at the general rate of 21%.

In each row, the first box is the taxable base, the second is the rate you apply and the third is the tax due. Watch out for one thing: the 303 does not ask how many invoices you issued, so don’t go looking for a box for the number of operations.

In Marta’s case, who only invoices at 21%, the row she needs is the third one:

• Box 07: 7,500.00 (sum of the taxable bases).
• Box 08: 21 (the rate).
• Box 09: 1,575.00 (7,500 times 0.21).

Boxes 01 to 06 stay at zero because she has no operations at reduced rates. If you invoice at 21% and go to the first row by instinct, you are declaring your services as if they were bread or books.

Boxes 10 to 26: special operations

These boxes cover intra-Community acquisitions (purchases from suppliers in other EU countries), reverse-charge operations, modifications of taxable bases and recargo de equivalencia (the equivalence surcharge regime for retailers). If the intra-Community acquisition boxes come out with figures, on top of the 303 you also owe the modelo 349.

If your activity is only with Spanish clients and suppliers, and you don’t apply recargo de equivalencia, all these boxes stay at zero. The vast majority of autónomos with a simple activity don’t touch anything here.

What throws people about intra-EU purchases. When you buy a service from a company in another EU country —a software subscription, say— the invoice arrives without VAT, and you still have to declare it. You self-charge it: the same amount appears twice, as output VAT in this block and as input VAT in the deductible one. The net result is zero — you pay nothing extra — but both entries have to be there. It looks alarming the first time; understanding that they cancel each other out is the whole trick. You also need an EU VAT number and form 349 for this.

Box 27: total output VAT due

It’s the sum of all the output VAT due. For Marta: 1,575.00 euros.

Block 2: deductible VAT (boxes 28 to 45)

This block gathers the VAT you’ve paid your suppliers and can deduct. Not every expense is deductible: only those directly related to your professional activity and which have a complete invoice with your tax details count.

And there’s a nuance almost nobody explains that changes the number: an expense can be deductible only in part. It isn’t yes-or-no, it’s a percentage.

The clear case is the car. If you use a passenger car for work and for your life, the law presumes it is used for the business 50%, so you deduct half the input VAT. That presumption can be rebutted both ways: you can prove greater business use, and the tax office can prove less. For some vehicles —goods or passenger transport, driving schools, commercial representatives, security services— the presumption is 100%.⁴

What matters for form 303: boxes 28 and 29 take the amount you actually deduct, not the one printed on the invoice. If the garage invoice shows 210 euros of VAT and your business use is 50%, box 29 takes 105.

And the other 105? It isn’t lost: the VAT you don’t deduct becomes more deductible cost in your income tax. It moves from one tax to the other, which is why it pays to set the percentage properly from the start rather than deciding it every quarter.

Boxes 28 and 29: purchases of current goods and services

This is where the bulk of your ordinary deductible expenses go.

• Box 28: 829.99 (sum of the taxable bases of the expenses).
• Box 29: 174.30 (sum of the VAT on those expenses).

Boxes 30 and 31: investment goods

If during the quarter you’ve bought an investment good –a computer, a camera, office furniture– whose amount exceeds 3,005.06 euros (net, without VAT), it’s declared here instead of in boxes 28-29. The VAT is still deductible, but it goes in a separate box because investment goods have special regularisation rules over the following years.

Marta hasn’t made any purchases of this kind this quarter, so boxes 30 and 31 stay at zero.

Boxes 32 to 43: other deductions

Imports, intra-Community acquisitions, agricultural regime compensations and other situations that don’t apply to most autónomos with a domestic activity. Leave at zero unless one of them applies to you.

Box 44: total to deduct

It’s the sum of all the deductible VAT. For Marta: 174.30 euros.

Block 3: result (boxes 45 to 71)

This is where everything is reconciled.

Box 45: difference

Box 27 minus box 44. That is, output VAT minus deductible VAT.

For Marta: 1,575.00 - 174.30 = 1,400.70 euros.

Box 46: amounts to offset from previous periods

If in some earlier quarter of the same year the result was negative and you chose to offset it (instead of requesting a refund), here you subtract that amount. If you have nothing pending, you leave it at zero.

Box 64: result of the settlement

It’s the result after applying offsets and other adjustments. For most autónomos it’s the same figure as box 45. Marta puts: 1,400.70 euros.

Box 65: exclusively for the last return of the year

In the fourth quarter (4T), this box allows you to include the annual regularisation of investment goods, if applicable. In the first three quarters it’s left at zero.

Boxes 66 to 69: annual result

These boxes are only filled in in the fourth quarter. They gather the overall result of the year, the offsets applied, the refund requested, etc.

Box 71: result of the settlement

This is the final number. It’s what you pay or what you get refunded.

For Marta, in the second quarter: 1,400.70 euros to pay.

If the result is positive, select “A ingresar” (to pay) and choose direct debit or direct payment with NRC. If it’s negative, select “A compensar” (to offset) to deduct the amount in later quarters, or “A devolver” (to refund) if you’re in the fourth quarter and you want the Agencia Tributaria to pay you the difference.

What happens if the result is negative

If in a quarter you’ve paid more VAT than you’ve charged –for example, because you had a large investment or a quarter with little income– the result of the settlement will be negative.

In the first three quarters of the year you have two options:

Offset: you leave that balance in your favour to subtract it in the next quarter. You mark “A compensar” in the relevant box and carry the amount forward.

Wait until the fourth quarter: in the last return of the year you can request a refund of the accumulated balance. It’s the only return in which the Agencia Tributaria refunds you money directly.

You can’t request a refund in the first, second or third quarter except in very specific cases (cessation of activity, for example). The usual thing is to offset and keep carrying it forward.

The most common mistakes

Not including all the deductible expenses. Every expense invoice with VAT that you forget to record is money you pay over the odds. Reviewing the quarter’s bank statement before filing the return is a habit that pays off.

Confusing the taxable base with the total amount. Box 02 asks for the taxable base, not the invoice total. If your invoice is for 2,420 euros (2,000 base + 420 VAT), in box 02 you put 2,000. It seems obvious, but under deadline pressure it happens more than it should.

Not keeping the invoices. The modelo 303 is a return, not a definitive settlement. The Agencia Tributaria can ask you for the original invoices in a later check. You need to keep them for at least four years.

Filing late. The modelo 303 deadlines are strict: in the common territory, from the 1st to the 20th of the month following the close of the quarter (except the fourth, until 30 January); in the Basque Country, until the 25th (with the fourth quarter in the annual modelo 390); and in Navarre, with the modelo F-69. You have them by territory at the start of the article. If you direct-debit the payment, the deadline ends five days earlier. Filing late, even by a single day, can trigger surcharges.

Deducting the full VAT on an expense that is only half yours. The car, the phone you use for everything, the room at home you turned into an office. The invoice shows one amount and your right to deduct is another: form 303 takes the one that applies to you, not the one printed. It’s one of the adjustments that comes up most in an inspection.

Forgetting the offsets. If the previous quarter came out negative and you marked “A compensar”, that amount should appear in box 46 of the next quarter. If you forget it, you’re giving up that balance in your favour.

Quick summary for Marta

Seven boxes with real figures, the rest at zero. That’s all an autónomo with a simple activity needs to fill in.

How does Cuéntamo help with this?

Filling in the modelo 303 by hand means adding up your invoices again, splitting the VAT by rate, and making sure the boxes are consistent with each other. If you keep your transactions in Cuéntamo, that work is already done: the self-employed module calculates the quarterly settlements from the transactions you’ve recorded, with output and input VAT broken down by rate. You just copy each total into its box on the Agencia Tributaria form.

The breakdown by VAT rate is expandable, so you can see which invoices make up each box and review them before filing. If a quarter comes out as carry-forward (VAT to compensate), the amount rolls over to the next one without you having to remember it.

Before tackling the full form, you can check the result with the quarterly VAT calculator. And if you want to understand where each number comes from, review how quarterly VAT is calculated.

And at year-end: the modelo 390

The four 303s of the year are later summarised in an annual return, the modelo 390, filed within the first thirty days of January. It isn’t a new settlement and it generates no payment: it’s the aggregate picture of the year, and the moment when mismatches a single quarter never reveals come to light. We cover it in what the modelo 390 is and how it ties to your 303s.

Frequently asked questions

What is the modelo 303 and who has to file it?

It’s the quarterly VAT self-assessment: you declare how much you’ve charged your clients (output VAT) and how much you’ve paid your suppliers (input VAT), and the difference is what you pay or what stays in your favour. Every self-employed person or company with VAT-liable activity files it, even for a quarter with nothing in it.

Which boxes of the modelo 303 do I have to fill in if I’m an autónomo with a simple activity?

If you only invoice at 21% to Spanish clients and your expenses are ordinary, just a few are enough: the output VAT boxes (01, 02, 03), the total output VAT due (27), the deductible VAT boxes (28, 29), the total to deduct (44) and the result boxes (45, 64 and 71). The rest stay at zero.

What do I put in box 02, the taxable base or the invoice total?

The taxable base, not the total. If your invoice is for 2,420 euros (2,000 of base plus 420 of VAT), in box 02 you put 2,000. It’s one of the most repeated mistakes.

What do I do if the result of my modelo 303 comes out negative?

In the first three quarters you can mark “to be offset” and carry that balance in your favour forward to the next quarter. The refund is only requested in the fourth quarter, except in specific cases such as cessation of activity.

Where do I declare the purchase of a computer or a capital asset?

If it exceeds 3,005.06 euros of taxable base it goes in boxes 30 and 31 (investment goods), not in 28-29, because they have their own regularisation rules. Below that amount it’s declared as an ordinary expense.

Can I deduct the VAT on my car in form 303?

If it’s a passenger car you use for work and for personal life, the law presumes 50% business use, so box 29 takes half the amount. You can deduct more if you can prove it, and the tax office can argue for less. For delivery vans, driving-school cars or commercial representatives’ vehicles the presumption is 100%. Whatever VAT you don’t deduct becomes deductible cost in your income tax.

Is the modelo 303 cumulative?

No. Each 303 covers only the operations of its settlement period (the quarter, or the month if you file monthly), so the third quarter does not include the first or the second. The one that is cumulative is the modelo 130 under the common territory: it is calculated on net income from 1 January to the end of the quarter, minus withholdings and earlier payments. The only thing carried forward on the 303 is the balance in your favour from a quarter that came out negative, until you offset it.

How long do I have to keep the modelo 303 invoices?

At least four years. The 303 is a return, not a definitive settlement, and the Agencia Tributaria can ask you for the original invoices in a later check.

If you keep your transactions in Cuéntamo, the amount for each box is already calculated for you on the quarterly settlements screen. You just have to copy the totals to the Agencia Tributaria form. Available at cuentamo.com.

Figures for 2026. The general (21%) and reduced (10%) VAT rates have been in force since 2012 (RDL 20/2012); the super-reduced rate (4%), since 1995 (Law 37/1992 on VAT).

This article is checked against official sources and reviewed periodically. If you spot anything out of date, email us at [email protected].