A typical month

An example for €4,000 gross a month, no pension and the tax credit applied (2026 rates, rounded):

The lines you will see

Loon in geld / brutoloon: Your gross salary for the period.
Loonheffing: Income tax and national insurance, withheld by your employer and settled later in your tax return.
Loonheffingskorting: The tax credit applied by your employer. Only one employer (or benefits agency) should apply it.
Pensioenpremie: Your share of the pension contribution, deducted before tax.
Bijzonder tarief: The withholding rate for bonuses, holiday allowance and 13th months: often higher than on your salary. Overpaid tax comes back in your tax return.
Reiskostenvergoeding: Travel allowance, tax-free up to €0.23 per km in 2026.
Thuiswerkvergoeding: Home-working allowance, tax-free up to €2.45 per day in 2026.
Werkgeverslasten: Employer costs on top of your salary (employee insurance, Zvw); shown for information.
Cumulatieven: Year-to-date totals; useful when you file your return.

1
Is the tax credit applied once?
Two jobs or a job plus a benefit with the credit on both means too little tax withheld and a bill later.
2
Is the right tax year table used?
In January, the new year's tables apply. A wrong table shows up as an unexpected net change.
3
Keep the annual statement (jaaropgaaf)
You need it for your tax return in spring; most figures are pre-filled from it.

Your yearly tax is settled in your return, so a bonus taxed at the high "special rate" is not lost. See filing your first return.