How is it calculated?
The calculator compares your gross salary against the decile boundaries published in the National Insurance Institute's latest wage report (first half of 2025 — actual employer-filing data covering about 4 million employees), with linear interpolation between boundaries. The result is an estimate, not an exact measurement.
Note that the distribution covers employees only and monthly gross pay. Self-employment income, capital income and part-time salaries change the picture — and gaps between industries, seniority and regions are large.