Foreign dividends
€1,000.00 − €263.75 − €40.00 = €696.25
The source country withholds first. In Spain the gross dividend is taxed in the savings base (19% to 30%) and you can deduct what you paid abroad up to a limit: the lower of the foreign tax capped at the treaty rate (usually 15%) and the Spanish tax on that dividend. On €1,000 from a German company, €263.75 is withheld; in Spain you pay €190 minus a €150 credit, €40. In total €303.75 (30.4%), against €190 for a Spanish company.
When a country withholds more than the treaty allows, the difference cannot be credited in your Spanish return: Germany withholds 11.375 points too much, Italy 11, Belgium 15 and Switzerland 20. It can only be recovered by claiming it from that country's tax authority, with forms, a tax residence certificate and deadlines of several years. The Netherlands (15%), the UK (0%) and the US with a W-8BEN form (15%) have no excess.
Choose the country; if your broker applies a different withholding, change it. Enter the gross annual dividend and your marginal savings rate. For simplicity the whole dividend is taxed at that rate; in practice it is added to the rest of your savings income for the year.
It is the declaration certifying to the US that you are not a US tax resident. With it, withholding drops from 30% to the 15% treaty rate. Your broker handles it, and it is valid until the end of the third year after signing.
By filing a claim with that country's tax authority (in Germany the Bundeszentralamt für Steuern; in Switzerland the ESTV with form 90) together with a Spanish tax residence certificate. Deadlines are around three to four years and the process may have a cost.
The Spanish tax agency only accepts up to the treaty cap. A January 2026 ruling by the Madrid regional High Court (TSJ) allowed the tax actually paid to be credited, but it is an isolated decision, not Spanish Supreme Court case law. The calculator applies the tax agency's criterion.
Withholding on the companies in the index is borne by the fund itself and cannot be credited in your return; what the ETF distributes is taxed in Spain as a dividend. Accumulating ETFs do not distribute, so tax is deferred until you sell.