To estimate extra tax, more details are needed: your country, tax year, income type, and your current income level. Without those, any number would be guesswork. Here’s a quick, practical way to gauge it yourself (assuming you’re in the Netherlands, since that was the most recent context in the sources you’re likely referencing):
- Identify your tax box: Most people are taxed in Box 1 (income from work and home) and Box 3 (savings/investments). If you have a mix, you’ll be taxed in multiple boxes.
- Gather figures:
- Gross annual income (salary, bonuses, etc.).
- Applicable tax credits (general and labor tax credits) and any other deductions you expect.
- For Box 3: total savings and investments as of 1 January of the year, minus any deductible debts, plus any tax-free allowances.
- Apply 2025 Dutch wage tax brackets (illustrative): the first bracket taxed at a lower rate up to a threshold, the second at a higher rate for income above that threshold. Exact rates and thresholds change yearly, so use the current year values from the Belastingdienst or a reputable calculator.
- For Box 3, compute your capital yield base, apply the tax-base share if you have a partner, and multiply by the Box 3 tax rate applicable for that year.
- Subtract tax credits to obtain net tax due, then compare with withholdings to estimate the “extra” tax due or refund.
If you can share:
- Your country and tax year,
- Your gross annual income (and any expected deductions/credits),
- Your approximate savings/investments and debts (for Box 3, if applicable),
I can walk you through a more precise calculation step by step.
