Living in one Spanish region or another means up to 3,152 euros a year of difference in income tax on the same 100,000 euro salary. That is the headline finding of the study "Income Tax by Region in Spain 2026" published by BMC, which computes effective IRPF rates in Madrid, Catalonia, Valencia, Andalusia and the Region of Murcia by applying the official scales of the Tax Agency's Renta Manual.
Effective rates, not marginal ones
Unlike the usual comparisons built on marginal rates, the study computes the full tax bill for five income levels (25,000 to 150,000 euros) with one homogeneous taxpayer profile: single, no children, aged 40, employment income only. The result shows the real impact of the regional scale on the final liability.
At the 100,000 euro level, Madrid applies the lightest effective rate (32.5%) and Valencia the heaviest (35.6%): 3,152 euros a year of difference on the same salary. At middle incomes the gap narrows, because the regional layer weighs more as the taxable base rises.
Open methodology
Every figure is computed directly on the state and regional scales in force and published with the methodology in plain sight and machine-readable data (Dataset schema, CC BY 4.0 licence), reusable by media, researchers and search engines. The full study is available in Spanish, English, French and German.
Tax residence: substance over form
The study also recalls that tax residence requires genuine presence (more than 183 days a year or the centre of economic interests in the territory). A purely formal relocation to capture a lighter scale is rejected by the Spanish Tax Agency, so any decision must start from a real, documentable move.