Progressive income-tax systems divide income into slices. Each slice is taxed at its own rate. Moving up a bracket does not mean your whole income is taxed at the higher rate — only the portion above the threshold is.
Germany has a smoothly progressive curve with marginal rates from 0% to 45% plus solidarity surcharge above EUR 18,130. France runs five brackets from 0% to 45% with a family-quotient adjustment for children. Italy operates three IRPEF brackets (23%, 35%, 43%) plus regional and municipal surcharges. Switzerland combines a federal scale with a cantonal scale, leading to very different effective rates across cantons.
Understanding brackets is essential for tax planning: contributions to pension pillars or charitable donations reduce taxable income and may push you into a lower bracket entirely.
A French single earner at EUR 50,000 pays 0% on the first 11,497, 11% on the next 17,818 and 30% on the remaining 20,685 — total tax of roughly EUR 8,165, an effective rate of 16.3%.