Modelo 303 step by step: the quarter's IVA, box by box

Step by step

1. The IVA you charge (IVA devengado): the base and the IVA of your invoices, by rate. At 21%, casillas 07, 08 and 09; there are rows for 10% and 4% too. A refund you issued goes in casillas 14 and 15, with a minus sign. The total is casilla 27.
2. The IVA you can deduct (IVA deducible): the IVA on what you buy for the activity (casillas 28 and 29) and on investment goods (30 and 31). The total is casilla 45.
3. The quarter’s result: casilla 46, casilla 27 less casilla 45.
4. Invoices without Spanish IVA are declared too, for information: to businesses in other EU countries (casilla 59), exports (60) and services not subject in Spain (120).
5. What earlier quarters left: a credit from before is casilla 110; what you use now, 78; what is still left for later, 87.
6. The result to file, casilla 71. Above zero, to pay (a ingresar). Below zero in the 1T to 3T, carried to the next quarter (a compensar, casilla 72). Below zero in the 4T, refunded (a devolver, casilla 73) or carried to next year: you choose.

An example: the 3T to carry forward, the 4T to pay

A made-up activity, worked out by Taxito’s own engine with the 2026 rules. In the 3T it charged €315 of IVA and paid €1,260 on a large expense: the 303 comes out at €945 to carry forward. In the 4T that credit is casilla 110, it is used in casilla 78, and the 303 comes out at €1,155 to pay.

The same activity’s income tax, quarter by quarter, is in the Modelo 130 article: Modelo 130: how the quarterly prepayment is worked out

When to file it in 2026

• 1T: April 1 – 20, 2026; by direct debit, until April 15, 2026
• 2T: July 1 – 20, 2026; by direct debit, until July 15, 2026
• 3T: October 1 – 20, 2026; by direct debit, until October 15, 2026
• 4T: January 1 – February 1, 2027; by direct debit, until January 25, 2027 expected: the AEAT has not published this date yet

Who it applies to

Every autónomo in the general IVA regime, every quarter, even one with no invoices. Employees do not file it.

How Taxito works it out

Box by box in the form's order, from your book; last year's 4T credit becomes casilla 110 of the 1T. Every amount opens its "¿Por qué?". Taxito never files it: you copy the boxes into the AEAT's form.

Official sources

• AEAT, Modelo 303 instructions: MIVA26 cap. 9
• Ley 37/1992 del IVA (BOE): art. 90.Uno LIVA; art. 91.Uno LIVA; art. 91.Dos LIVA
• AEAT, Calendario del contribuyente 2026
• Orden EHA/1658/2009, direct debit (domiciliación) (BOE)

Verified on October 16, 2026. Taxito reads each figure on its source and says when it was read.

Estimates, not tax advice. Taxito never files anything for you: you check the figures and file them yourself.

More in the Guide

• Modelo 130: how the quarterly prepayment is worked out, quarter by quarter
• Self-employed and employed at once: how both incomes come together in the Renta
• Taxito’s home page