In short: Gross pay is the amount written in your employment contract before the employee's social security contributions and income tax are deducted; what reaches your account is the smaller net pay.
Simply put: Gross is the whole cake before it is cut. Contributions for pensions, health, sickness and unemployment, and income tax, are taken from it. Use gross to compare job offers and for credit applications; use net for your monthly budget. The employer also pays its own contributions on top, so a job costs the employer more than the gross.
Example: A job advert says "€1,500 gross". That is not what will arrive in your account — net pay is lower by the deductions.
General rule: The EU does not set income tax or contribution rates; each country does.
Example: Bulgaria — on €1,500 gross (born after 1959, universal pension fund), employee contributions are 13.78 % (€206.70), tax is 10 % of the rest (€129.33), and net pay is €1,163.97. Rates as at 19.10.2026 (Social Security Code, Article 6; Personal Income Tax Act, Article 42).
Check in your country — Ask whether a quoted salary is gross or net; the tax authority often publishes an official net-pay calculator.
Source: Regulation (EC) No 883/2004: https://eur-lex.europa.eu/eli/reg/2004/883/oj · NSSI (Bulgaria): https://www.noi.bg/dohod01082026/