There is no universal percentage that every Spanish freelancer should save. A more useful quarterly reserve adds two figures: the net VAT that would be payable on form 303 and the estimated form 130 income tax instalment. If either figure is negative, use zero for that part of the reserve.
Tax reserve = max(0, output VAT − deductible input VAT) + max(0, estimated form 130 payment).
Use your own figures in the free tax reserve calculator. No sign-up is required.
Set VAT aside first
VAT collected from a client is not free cash. Form 303 compares output VAT on sales with eligible deductible input VAT. A positive result is the first part of the reserve. If the result is carried forward, do not use it to reduce income tax in this estimate: it remains a VAT balance for another period.
Not all input VAT is deductible. The cost must be linked to the activity and properly documented, and some cases allow only partial or no deduction. The Spanish Tax Agency explains deductible VAT and the 2026 pre-form 303.
Then estimate form 130
Form 130 does not use the latest quarter alone. It starts with cumulative income and deductible expenses since 1 January, applies 20 % to positive profit, and deducts withholdings and earlier instalments. Simplified direct assessment may also include the hard-to-justify expense allowance, subject to its annual cap.
The official form 130 instructions set out the cumulative calculation. Professionals may be exempt from filing when at least 70 % of qualifying income is subject to withholding. Withholdings are already income tax advances paid in by clients.
Example: a €3,200 reserve
Take a first quarter with €10,000 of income and €2,000 of expenses, all at 21 % VAT, with expense VAT fully deductible:
- Output VAT: €2,100.
- Deductible input VAT: €420.
- VAT portion of the reserve: €1,680.
- Cumulative net profit: €8,000.
- Hard-to-justify expenses at 5 %: €400.
- Indicative form 130 base: €7,600; 20 % is €1,520.
With no withholdings or earlier instalments, the reserve is €1,680 + €1,520 = €3,200. With €750 of withholdings, form 130 would fall to €770 and the reserve to €2,450. This is why a fixed percentage of turnover can mislead.
A monthly routine without a fixed percentage
- Record every sales and purchase invoice, keeping the net amount, VAT and withholding separate.
- At month-end, recalculate the quarter's form 303 and the year's cumulative form 130.
- Compare the target with the money already reserved and transfer only the gap.
- Recalculate after a large invoice or cost, not just at quarter-end.
This avoids two common mistakes: spending VAT collected from clients and reserving income tax on gross turnover without allowing for costs, withholdings or earlier payments.
What this formula does not cover
This is an operating provision, not the final annual income tax bill. The annual return uses state and regional bands, personal circumstances, other income and tax credits. VAT can also change under pro rata deduction, cash accounting, the equivalence surcharge, OSS, intra-Community transactions and balances from earlier periods. Check the result with an adviser if any of those apply.
Sources and editorial method
This guide uses the same cent-based calculation engine as Aurio's public calculators and app. The formula has been checked against the Spanish Tax Agency instructions linked above. Review date: 12 August 2026. Aurio calculates and explains; it does not file returns or replace professional judgement.
