Box 3 — what does it actually do to my savings?
Actual-return choice vs flat-rate, exemption, reference date Jan 1, how savings vs investments vs debts are treated. With your own numbers.
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In short
Box 3 is the tax on your wealth: savings, investments, second home, debts. Since 2026 you may choose between two systems (transitional period toward full actual-return in 2028). (1) Flat-rate system: government estimates return per category — savings 1.03%, investments 6.17%, debts −2.57%. Rate 36% on difference between estimated return and exemption. (2) Actual-return: your actual interest + dividend + capital gains. Rate 36%. Exemption 2026: €57,684 single, €115,368 with fiscal partner. Above that you're taxed. Reference date is 1 January: your wealth on that day determines tax for the whole year. Rule of thumb: mostly cash (low actual rate) → actual-return better. Investments that underperformed → actual-return better. Average mix in a good investment year → flat-rate better. Example: €100k cash + single: flat-rate = (1.03% × €42,316) × 36% = €157 tax. Actual at 2% rate: (€42,316 × 2%) × 36% = €305 tax. Flat-rate wins here. Choice annually: you may switch systems each year via Mijn Belastingdienst.
You enter
- Cash + checking accounts on 1 January — All bank balances in NL and abroad. NL banks report automatically; foreign banks self-declare.
- Investments on 1 January — Stocks, ETFs, bonds, crypto, mutual funds. Market value on that day. Crypto: exchange rate + portfolio on 1 Jan.
- Debts on 1 January — Personal loans, revolving credit, debts >€3,700 (2026 threshold). DUO student debt NOT counted. Own-home mortgage NOT counted either.
- Second home / rental property — WOZ value on 1 January. Not your own home — that's in Box 1 (imputed value + mortgage interest).
- Actual returns (for choice 2) — Interest received + dividends + investment price changes. For actual-return system.
- With fiscal partner — Exemption doubles (€115,368). Wealth can be split optimally between partners.
You get back
- Box 3 tax flat-rate system — What the flat-rate route costs (based on government return estimate per category).
- Box 3 tax actual-return system — What actual-return costs (based on your real numbers).
- Which choice is more favorable — Recommendation with side-by-side numbers. Difference in euros per year.
- Tax-free exemption used — How much of your wealth falls under the €57,684 exemption.
- Effective Box 3 tax % of wealth — What you actually pay as % of total wealth. Shows how Box 3 eats into wealth growth.
The math behind it
Box 3 tax = (Taxable return) × 36%
Flat-rate system: for each category “estimated return” is applied to value on 1 January, proportional to the share above the exemption.
• Cash + bank accounts: 1.03% estimated return.
• Investments + second home: 6.17%.
• Debts: −2.57% (negative = deduction).
Taxable return = sum of (category value × return %) × (wealth above exemption / total wealth).
Actual-return system: sum your actual interest + dividends + price gains (incl. unrealised), subtract the exemption share, × 36% tax.
Exemption 2026: €57,684 individual / €115,368 partners. Reference date: 1 January of the tax year. What you own on 1 Jan counts for the whole year; wealth changes during the year don't count.
Flat-rate system: for each category “estimated return” is applied to value on 1 January, proportional to the share above the exemption.
• Cash + bank accounts: 1.03% estimated return.
• Investments + second home: 6.17%.
• Debts: −2.57% (negative = deduction).
Taxable return = sum of (category value × return %) × (wealth above exemption / total wealth).
Actual-return system: sum your actual interest + dividends + price gains (incl. unrealised), subtract the exemption share, × 36% tax.
Exemption 2026: €57,684 individual / €115,368 partners. Reference date: 1 January of the tax year. What you own on 1 Jan counts for the whole year; wealth changes during the year don't count.
Worked example
Pieter and Lara, fiscal partners, on 1 January 2026:
• Cash: €60,000
• Investments (ETFs): €80,000
• Personal loan debt: €5,000
• Total wealth: €135,000
• Partner exemption: €115,368
• Taxable wealth: €19,632
(A) Flat-rate system:
Estimated return on total wealth:
• Cash: €60,000 × 1.03% = €618
• Investments: €80,000 × 6.17% = €4,936
• Debts: €5,000 × −2.57% = −€129
• Total: €5,425
Proportion above exemption: €19,632 / €135,000 = 14.5%
Taxable return: €5,425 × 14.5% = €787
Box 3 tax flat-rate: €787 × 36% = €283.
(B) Actual-return (2026 figures):
• Interest on cash 1.8% = €1,080
• Dividends ETFs 2% = €1,600
• Price gain ETFs 8% = €6,400
• Loan interest −5% = −€250
• Total actual return: €8,830
Proportion above exemption: 14.5%.
Taxable actual return: €8,830 × 14.5% = €1,280
Box 3 tax actual: €1,280 × 36% = €461.
Conclusion: flat-rate wins €178/yr for them because their actual investment return (8%+2%) exceeds the 6.17% estimate. Recommendation: choose flat-rate this year. Re-evaluate next year — in a poor stock year, actual-return would be better again.
• Cash: €60,000
• Investments (ETFs): €80,000
• Personal loan debt: €5,000
• Total wealth: €135,000
• Partner exemption: €115,368
• Taxable wealth: €19,632
(A) Flat-rate system:
Estimated return on total wealth:
• Cash: €60,000 × 1.03% = €618
• Investments: €80,000 × 6.17% = €4,936
• Debts: €5,000 × −2.57% = −€129
• Total: €5,425
Proportion above exemption: €19,632 / €135,000 = 14.5%
Taxable return: €5,425 × 14.5% = €787
Box 3 tax flat-rate: €787 × 36% = €283.
(B) Actual-return (2026 figures):
• Interest on cash 1.8% = €1,080
• Dividends ETFs 2% = €1,600
• Price gain ETFs 8% = €6,400
• Loan interest −5% = −€250
• Total actual return: €8,830
Proportion above exemption: 14.5%.
Taxable actual return: €8,830 × 14.5% = €1,280
Box 3 tax actual: €1,280 × 36% = €461.
Conclusion: flat-rate wins €178/yr for them because their actual investment return (8%+2%) exceeds the 6.17% estimate. Recommendation: choose flat-rate this year. Re-evaluate next year — in a poor stock year, actual-return would be better again.
How to read the result
- Reference date 1 Jan — timing wealthWealth on 1 Jan = tax base for whole year. Trick: make large purchases (car, renovation, prepay vacation) just before 1 Jan to lower reference wealth. Or temporarily pay down debt — cash gone + debt lower = wealth drops. Empty savings end Dec + return 2 Jan — provided it's not a sham-transaction the Tax Office can reverse.
- Own home does NOT count in Box 3Common confusion: your own home + mortgage sits in Box 1 (imputed value + interest deduction). NOT in Box 3. Beware money in offset-account against mortgage — sometimes counts. Second home, recreational property, rental: DOES count in Box 3.
- €3,700 debt threshold reduces taxDebts above €3,700 per partner (2026) reduce Box 3 wealth. Below: not deductible. So personal loan of €3,500 doesn't count. Mortgage on 2nd home: counts (no threshold exclusion for real-estate debt). DUO student debt: never deductible in Box 3.
- Actual-return helpful in losing yearOn investment loss (red year): actual-return = possibly €0 or even negative taxable. Flat-rate would still tax you at 6.17% estimated. So in a 2022-style loss year actual-return literally pays no tax. Flat-rate is administratively resettable via counter-proof route on strongly negative actual return.
- Partners: exemption doubles + split wealth optimallyWith fiscal partner: exemption €115,368 instead of €57,684. Plus: wealth can be fiscally split (50/50 or actual ratio). On €100k wealth + 1 partner: 100% to you = taxed on €42k. Split 50/50: 50% each × €57,684 exemption each = 100% free. Saves ~€150/yr here. Always split!
Key terms
- Reference date
- 1 January of the tax year. What you own that day determines Box 3 tax for the entire year.
- Flat-rate system
- Tax based on government-estimated return per asset category. Simple + predictable but sometimes unfair to those who earn less.
- Actual-return system
- Tax based on your actual interest + dividends + capital gains. Fairer but more admin + more complex.
- Exemption 2026
- €57,684 individual, €115,368 fiscal partners. Below this: no Box 3 tax.
- Debt threshold
- €3,700 per partner (2026). Debts above this are deductible from Box 3 wealth. 2nd home mortgage counts without threshold.
- Fiscal partner
- Married or registered partnership, or cohabiting with shared child, or cohabiting with joint owned home. Doubles exemption + enables optimal split.
- Counter-proof
- On strongly negative actual return (loss year) you can have the flat-rate system lowered via counter-proof. Specific procedure at Tax Office, especially relevant after Supreme Court ruling 2024.
Frequently asked
Does my pension pot or lijfrente count in Box 3?
NO. Pension rights (employer or professional pension) and lijfrente savings pot are exempt — they'll be taxed later as benefit in Box 1, avoiding double taxation. Do count: cash in “regular” account, investment account, crypto portfolio.
How do I report foreign wealth?
Mandatory via Mijn Belastingdienst: foreign bank account, investment depot at foreign broker (Interactive Brokers, Trade Republic, Degiro foreign version), shares held directly, foreign real estate. Not reporting = serious tax fraud (fine up to 300% + criminal). Since CRS regulations the Tax Office exchanges data with >100 countries — assumption that “no one sees it” is wrong.
What changes 2026 vs 2025?
Most important: choice between flat-rate and actual-return legally anchored (was procedurally possible via counter-proof since Supreme Court ruling 2024). Estimated-return percentages: cash 1.03% (was 1.44% in 2025) — declining with rate cuts. Investments 6.17% (was 6.17%, unchanged). Exemption slightly up from €57,000 to €57,684. Rate 36% stays. 2027-2028: phase-in/out toward full actual-return.
Crypto: how to value?
Market value on 1 Jan 23:59 local Dutch time, in euros. Use exchange rate from reliable source (CoinMarketCap, CoinGecko, your exchange report). Keep proof: screenshot or CSV export. Staking/yield farming: tokens received = actual return under actual-return system. NFTs: estimate market value, hard — on doubt value low (Tax Office-friendly). Crypto across multiple addresses: count everything.
Forgot Box 3 declaration in old years — what to do?
Voluntary correction (suppletie) via Voluntary Disclosure: file return now, pay back tax + interest + lower fine (vs discovery by Tax Office). Goes back 5 yrs (extendable to 12 yrs on foreign wealth). Tip: do it yourself BEFORE Tax Office discovers — on discovery: fine up to 300% + possible criminal prosecution. Voluntary Disclosure is tax advisor specialty, often worth the €500-1500 to guide properly.
Complex situations
Edge cases that typical net-pay tools skip but actually matter for a real Dutch tax situation. Each one assumes the basic case above and tells you what changes.
Second home or rental — Box 3 not Box 1
Rented-out home, vacation home, recreational property: fully Box 3. Not your main residence (stays Box 1 with imputed value). Valuation: WOZ value on 1 Jan. Mortgage on 2nd home: deductible from Box 3 wealth (no debt threshold for real-estate debt). Effect: 2nd home €300k − mortgage €200k = net €100k extra wealth in Box 3. Taxable: after exemption €57,684, so €42k × 6.17% × 36% = ~€935/yr extra. Rental income: not separately taxed in Box 3 flat-rate (already presumed in 6.17% estimate). In actual-return: add rent + value increase.
Crypto portfolio — valuation + burden of proof
Crypto treated as investments in Box 3 (6.17% category). Valuation moment: 1 Jan 23:59 NL time, in euros at reliable-source exchange rate. Keep minimum: screenshots wallets + exchange reports (Binance, Bybit, Coinbase export CSV) + euro-rate proof per day. Staking + yield farming: tokens received are return = taxed in actual-return year, not first at sale. NFTs: hard to value, honest estimate suffices. Defi positions: liquidity pool tokens = value of underlying positions. Tax Office gets data from NL exchanges (Bitvavo, Bitstamp NL) since 2023 — hiding not safe anymore.
Family debts — loan or gift?
“Loan” from parents/family: only Box 3 deductible if real loan agreement exists + minimum 6% interest paid (anti-tax-deferral rule). Otherwise: Tax Office treats as gift → falls under gift tax (annual exemption €6,890 parent-child 2026), not Box 3 deduction. Tip: set up loan agreement with notarial hand-note (or registered agreement), charge interest, do it for real — otherwise “for the tax office” loan is only on paper.
Counter-proof route on real negative returns
Since Supreme Court ruling December 2024 + 2026 Tax Plan: on demonstrable lower actual return than flat-rate system assumes, you can offer counter-proof. Especially relevant in stock crashes (2022 / 2008-style). Procedure: at filing tick “actual return lower” + send proof (bank statements, stock reports, dividend payments). For years before 2026: refund procedure still possible over recent years if you paid flat-rate but actual return was lower. Many people lose money unnecessarily — check old assessments 2017-2024.
Box 3 split between partners (optimal allocation)
With fiscal partners: wealth can be allocated for Box 3 return. Not mandatory 50/50: any split possible. Strategy: put as much wealth as possible with partner with lowest total income (sometimes unused tax credits). Or: split so both partners sit up to the €57,684 exemption. Example: €115k total wealth. With €80k at A + €35k at B = A pays over €22,316. Split 50/50: both €57,500 = both just under exemption = ZERO tax. Saves ~€160/yr here. No transfer needed — just declaration allocation. Bank ownership stays as is.
What this tool doesn't do
This tool calculates Box 3 tax for typical private wealth in the Netherlands. Many complex situations are worked out above. Out of scope: substantial-interest shares (Box 2 separate), pension rights (exempt), family loans below €3,700 (no deduction), exotic derivatives (futures, options — specialist advice). For your actual Box 3 assessment: Mijn Belastingdienst + all wealth components correctly filled + tax advisor on doubt.