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🔥 How this calculator works

This page explains everything the engine models, country by country, and — just as important — everything it does not. The calculator is a planning estimate, not advice; the goal of this page is that you never have to guess what's behind a number.

The engine, end to end

Everything is in today's money

All amounts are real (inflation-adjusted). Investment growth uses the real return — your nominal return minus inflation — so a result of "$1.8M at 55" means $1.8M of today's purchasing power. Income growth is treated the same way.

Three account buckets

Your wealth lives in three buckets that are taxed differently: tax-deferred (401(k), RRSP, SIPP, super…) — taxed as income on the way out; tax-free (Roth, TFSA, ISA…) — never taxed again; and taxable (brokerage), where only the gains are taxed, at your country's capital-gains inclusion rate. The taxable bucket tracks cost basis through every contribution and withdrawal.

Working years

Income tax is computed from your gross salary using your working country's real brackets (and your state/province/canton's second layer where one exists). Tax-deferred contributions reduce taxable income. Couples are taxed separately per person — or jointly (US married-filing-jointly brackets; German/French income splitting) where supported and selected.
Contributions compound monthly into the three buckets and grow with your income-growth assumption. This year's contributions are validated against your country's registered-account limits (a warning appears if you're above them).
Life costs: your stated savings rate already covers today's budget, so only changes versus today hit the projection — a future home purchase, a child arriving, a loan being paid off (which frees its payment), an ended mortgage. One-off costs (down payment + purchase taxes, education funds, car replacements) are always charged in the year they happen.
Net-wealth taxes (Switzerland, Norway, Spain, Dutch Box 3) are charged annually on the portfolio while you're resident.

The FIRE number and retirement age

Your FIRE number is the pot that funds your actual retirement plan, built from the same year-by-year cash flows as the projection below — so the headline stays consistent with the simulation instead of being a separate, rosier guess. The number is the smallest pot whose Monte Carlo success at the age you retire meets the certainty target you choose (default 90%), so it's sized to last through bad-market sequences rather than an average one — the smaller pot that would merely survive an average market is shown as a floor beneath it. The breakdown starts from permanent lifelong spending (everyday living and healthcare), then adds the present value of each time-limited cost, counted only for the years you'll actually pay it — a mortgage until it's paid off, children until they're grown, a car replaced every so often — rather than treating a 25-year cost as if it lasted forever. Then we subtract the pensions and other income you'll receive, since those reduce what your portfolio must cover. Everything is grossed up for the tax on withdrawals, evaluated at the age you actually retire. You can retire the moment you reach the number, or at a target age (the plan shows the risk if that's earlier than fully-funded).

Cost of living by city. Your everyday retirement spending — and therefore your FIRE number — can be scaled to where you actually retire. Pick a retirement city and the engine multiplies your day-to-day spending by that city's typical rent relative to the country's national average (bounded to a 0.5–3× range, so a single city can't distort the plan). Leave it on the national average for a typical city. This scales only everyday spending; housing and healthcare are set separately, with their own inputs.

Retirement, year by year

Withdrawals follow your chosen order (tax-smart default, deferred-first, or tax-free-first) and strategy (constant spending, guardrails, fixed percentage, or VPW). Each year the engine solves for the gross withdrawal that nets your spending need after that year's full tax picture.
That tax picture is age-aware: income tax in your retirement country, Canada's OAS clawback, US Medicare IRMAA surcharges from 65, and (opt-in) the US ACA premium subsidy before 65 — including its hard 400%-of-poverty-line cliff. Roth conversions and forced withdrawals are priced against the same rules, so the engine sees a conversion push you over the ACA cliff or into a clawback.
Forced minimums — US RMDs, Canadian RRIF minimums, Australian pension-phase minimums — follow the account's country (your 401(k) keeps US rules even if you retire abroad). Forced amounts beyond your spending are taxed and reinvested in the taxable bucket.
Conversion ladders (Roth/RRSP-style) move tax-deferred money to tax-free in low-income years up to your chosen taxable-income target, paying the marginal tax along the way.
Pensions (state and private) start at their own ages, convert from their own currencies, and are taxed as income. Estimators are built in for US Social Security, Canadian CPP/OAS, UK State Pension, German Rente, Dutch AOW, Australian Age Pension, Japanese Nenkin, and Singapore CPF LIFE.
Zakat (optional, sharia mode) — turn this on under "Tax on withdrawals" and the engine charges the obligatory 2.5%-a-year alms on your zakatable wealth (above the nisab, ≈85g gold) every year, while you save and in retirement. It's modelled on your liquid portfolio, so it delays your FIRE date and draws the pot down over time. Zakat is alms, not a tax, so it's tracked and shown separately. (Whether locked retirement accounts are zakatable is debated among scholars; we apply it to the full portfolio — the higher, more conservative reading. Adjust your own figure if your interpretation differs.) With sharia mode on, the contextual tips also switch to their halal variants — halal investing (screened index funds and sukuk instead of conventional interest-bearing bonds) and Islamic home financing (murabaha / ijara instead of an interest-charging mortgage).
Estate taxes at the end of the plan: progressive schedules for France, Japan, Korea; Germany's full-amount rate table; flat-above-allowance for the US and UK (allowances doubled for couples); Canada's deemed disposition (the remaining RRSP/RRIF taxed as final income plus realized gains).

Big one-off expenses & account access

When a big planned cost lands — a home down payment, a car, an education lump — the engine funds it the way you actually would: from taxable savings first, then tax-free, then tax-deferred, and it charges the real tax each draw triggers. A pension / 401(k) / RRSP withdrawal is taxed as income, stacked on that year's salary while you're still working — which is exactly why funding a house from it is so expensive. Realized gains in the taxable bucket pay capital-gains tax; nothing is drawn as tax-free money any more.

Locked accounts stay locked. A pension you can't legally touch yet — a UK pension before your cohort's access age (55, rising to 57 in April 2028), Australian super before 60, and similar — is skipped, not raided. If your accessible savings can't cover the expense, the plan tells you there's a shortfall and roughly how many years you need to bridge, instead of inventing pension money. Early withdrawals that are allowed but penalized (US before 59½, Singapore SRS before 63) show the penalty on top of the tax.

First-home schemes are modelled where they exist. Canada's Home Buyers' Plan and FHSA, the UK LISA, Australia's FHSSS and New Zealand's KiwiSaver first-home withdrawal each let a first-time buyer take a capped amount tax-free (or penalty-free) from an otherwise-locked or taxable account for a qualifying purchase — the engine draws these first and applies each scheme's own per-person cap and rules.

Contribution room the law gives back is modelled. A Canadian TFSA or Japanese NISA withdrawal restores that room the following year, and the plan redirects future contributions to refill it; room that's gone for good (RRSP, ISA, 401(k)) instead triggers a warning, so you can see what a withdrawal costs beyond the immediate tax.

Recently improved — why some figures changed

Several country tax rules were sharpened, so your numbers may differ from before — all of these are now more accurate, not less: US long-term capital gains are taxed at the real 0/15/20% brackets stacked on ordinary income, plus the 3.8% NIIT (rather than an income-tax proxy); Ireland's fund/ETF exit tax is 38%; retirement withdrawals are now tax-free in Hong Kong, Malaysia, the Philippines and (from 55) Thailand; pension lump-sum tax is concessional in China, South Korea and Switzerland rather than at full marginal rates; and the Netherlands Box 3 and Sweden ISK wealth/deemed-return taxes are refreshed to their current rates (with pensions excluded from the wealth base).

Account fine print now modelled. A US Roth conversion carries its own 5-year clock (converted money withdrawn too early pays the 10% penalty; your contributions always come out free); a UK LISA withdrawn before 60 for anything but a first home claws back 25%; a Canadian FHSA contribution is deducted from your income tax like an RRSP; and a tax-free wrapper you built in one country isn't always recognised as tax-free where you retire — a US Roth is respected in Canada and (for qualifying withdrawals) the UK, but a Canadian TFSA or UK ISA is taxed as an ordinary investment account abroad. The plan warns you when this applies.

Risk: Monte Carlo

Alongside the deterministic path, 1,000 full-lifetime simulations draw lognormal yearly returns around your expected return and volatility. Every simulation runs the same tax, RMD, conversion and life-cost logic. The success rate is the share of runs where the money lasts to the end of the plan; spending-flexibility metrics show how often a guardrails strategy would have cut spending.

Currencies

The plan's base currency is your retirement country's. Salaries earned elsewhere are taxed in their own currency via your editable exchange rate; any money field (and any pension row) can carry its own currency through the small picker beside it, converted at live European Central Bank rates (cached daily, with built-in fallbacks offline).

Guidance layers

On top of the projection: a budget guide comparing your categories against guideline shares of net income; a savings-allocation advisor that orders every dollar you save (employer match → first-home accounts → education grants → special accounts → bracket comparison between deferred and tax-free → taxable); levers showing what most moves your date; withdrawal-order comparison; scenario pin & compare; and a year-by-year CSV export whose tax column sums exactly to the headline lifetime tax.

Privacy

Everything runs in your browser. Your plan — incomes, balances, ages, the countries you choose — persists in your browser's local storage and never leaves your device. Saved plan files can be encrypted with AES-256-GCM (key derived from your passphrase with PBKDF2, 310k iterations).

For product analytics we use privacy-preserving, cookieless measurement — aggregate page views and anonymous usage events (for example, that the guided setup was opened), together with your interface language. No cookies, no identifiers, no cross-site tracking, and never any of your plan data. Do Not Track and Global Privacy Control are honored; full details are in the site's Privacy Policy. The other network calls: the daily exchange-rate fetch (from frankfurter.app, a mirror of the European Central Bank's published rates) and the Google Fonts stylesheets/font files the pages load — a request to Google's servers that, like any font CDN, carries your IP address and browser details.

What's modelled for each country

This table is generated from the same data registries the engine runs on — if a feature isn't listed here, the engine genuinely doesn't apply it for that country.

Country	Modelled

What this calculator does NOT model

Be skeptical of any tool that won't show you this list. Known simplifications and exclusions:

Contribution-room tracking over time. Limits are validated for this year's contributions and used by the advisor, but the engine does not track your personal carry-forward room (CRA/HMRC balances) year by year.
Dividend vs. capital-gains taxation. The US long-term capital-gains brackets (0/15/20%, stacked on ordinary income) and the 3.8% NIIT are modelled exactly since v1.4, as are the UK's 18/24% CGT bands and several countries' retail exemptions. Named investment wrappers now carry their own real tax treatment rather than the flat bucket rate: a Danish Aktiesparekonto is taxed at 17% mark-to-market, an Irish ETF at 38% on an 8-year deemed disposal, a French PEA within its €150k cap and ~18.6% social charges, an Italian PIR within its €40k/€200k caps and 5-year hold, and a Korean plan can flag a foreign-share portion taxed at 22%. Other countries' taxable-account returns are still taxed at withdrawal via a single inclusion fraction approximating the effective rate. An annual dividend/interest tax drag on the taxable account is applied each year (an editable ~2% yield assumption taxed through each country's yield or capital-gains rules — the US via the qualified-dividend/LTCG schedule, Canada via the eligible-dividend credit split); AU franking credits are still not modelled.
VAT / sales taxes — implicitly inside your spending figures, never added on top.
City/municipal income taxes below the state/province/canton layer (e.g. German church tax), and US AMT.
US Medicare IRMAA surcharges use the correct 2026 bands — currently priced on the single-filer bands with a single surcharge for couples too (joint thresholds and per-beneficiary pricing ship with the US engine update). Still simplified: the real two-year MAGI lookback (2026 premiums are set by 2024 income) is priced off current-year income instead, so a large one-off realization shows its IRMAA effect in the same year rather than two years later.
US Social Security taxation follows the IRS "provisional income" rules since v1.3 — 0% to 85% of the benefit is taxable by income band, with the statutory (deliberately un-indexed) thresholds. Spousal and survivor claiming strategies are still not optimized for you (see below).
US ACA healthcare (pre-65). When the ACA subsidy is on, the healthcare figure is treated as your gross plan premium before the credit — the engine then applies the income-based premium tax credit on top (correctly capped at that premium, so a plan cheaper than your subsidy nets to ~$0, exactly as real marketplace plans can). Enter the full premium, not your after-subsidy cost, or the credit is double-counted. Out-of-pocket costs beyond premiums (deductibles, copays) aren't separately modelled.
The headline FIRE number is simulated, with a simplified breakdown. The headline is the smallest pot whose Monte Carlo success at your retirement age meets the certainty target you choose (default 90%) — taxes, pensions and forced minimums modelled age by age across 1,000 lognormal-return simulations, not a rule-of-thumb multiple. Because it's sized to last through bad-market sequences, it prices sequence-of-returns risk directly; the smaller pot that merely survives an average market is shown as a floor beneath it. The breakdown popover's closed-form rows still share one blended tax rate for time-limited costs, with an explicit "simulation refinements" line reconciling them to the exact number.
Accounts left in other countries are captured (balances, their own currency) and their forced-minimum rules follow each account's origin (a frozen RRSP starts RRIF minimums at 72 even inside a US plan) — blended by each origin's share of your tax-deferred money, an approximation that assumes the slices grow and draw down proportionally.
One-off funding fine print. Account access ages, penalties, first-home schemes and contribution-room restoration are modelled (see "Big one-off expenses" above). Still simplified: scheme eligibility uses "you don't currently own a home" as the first-time-buyer test; tax withholding-vs-final-settlement timing, intra-year deadlines, US SEPP method choices, and starting Roth/FHSA basis (asked in the wizard, with a default) are approximations.
Australian superannuation. Concessional contributions are deducted at your marginal rate and then charged the 15% fund contributions tax (only 85% is invested), and super withdrawals are tax-free from age 60 (pension phase) — matching Australia's treatment. Still simplified: the ~15% tax on fund earnings during accumulation (lower in practice after the CGT discount and franking credits, and nil once in pension phase) is not separately applied, so the super balance grows slightly faster than reality (the preservation age of 60 itself is enforced — see "Big one-off expenses").
Payroll contributions. For Canada (2026), CPP + CPP2 and EI (plus Québec's QPIP and lower EI rate) ARE deducted from working-years take-home — so a gross-income entry yields a realistic net, and the savings capacity the wizard derives from it is payroll-adjusted (self-employed pay both CPP halves and no EI). They're treated as a cash outflow, not an income-tax deduction. For the US, FICA payroll (Social Security + Medicare) is not yet deducted — a US gross-income entry overstates take-home by the payroll share until the US engine update ships; elsewhere — UK National Insurance and similar — payroll is still not deducted.
Historical backtesting. Risk is modelled with Monte Carlo, not replayed historical sequences — we won't fabricate a data set.
Asset allocation & glidepaths. One expected return + volatility for the whole portfolio; no stock/bond split, rebalancing, or age-based de-risking.
Income-driven planning. Savings are what you state, not derived income-minus-spending; raises change contributions only through your growth assumption.
Currency risk. Exchange rates are snapshots, not simulated — a cross-border plan carries FX risk the Monte Carlo doesn't see.
Home equity. Your home isn't a withdrawable asset (no sale-downsize modelling, no reverse mortgage); rent vs. buy compares cash flows only.
Rental/business income beyond what you add manually as recurring cash flows; defined-benefit pension valuation beyond the monthly figure you enter; annuity purchases (except Singapore's CPF LIFE estimate).
Citizenship-based taxation is modelled for US citizens (the dominant case): abroad, you pay ≈ the higher of your residence country's tax and US tax (the foreign-tax-credit outcome), with the FEIE (~$126,500) sheltering salary first. Simplifications: treaty re-sourcing rules, PFIC fund taxation, state filing obligations, and foreign recognition of Roth accounts are not modelled.
Tax-treaty specifics. Cross-border plans tax salary in the work country and retirement income in the residence country — a reasonable default, but treaty withholding rates, totalization agreements, and pension-portability details are simplified.
Cross-border state pensions. A plan whose work and retirement countries differ seeds both government pensions at their full amounts — realistic only if you contributed enough years in each. A career spent mostly in one country earns mainly that country's pension, so refine both figures with the pension estimator (or the wizard's contribution-year question) rather than trusting the default.
Spousal optimization details — Social Security spousal/survivor claiming strategies, and spousal RRSPs. On filing status: joint-filing systems (US MFJ, German/French splitting, plus LU/PT/PL elections and the French quotient familial since v1.3) apply the joint schedule in both working and retirement years once you tick "file jointly," and revert to single after a survivor is widowed. Where couples file individually (UK, Australia…), retirement draws are taxed per person since v1.3, split to equalize incomes. For Canada (2026), pension-income splitting and a per-person OAS clawback are modelled — a 65+ couple's eligible pension income is notionally shared to minimize combined tax, and each spouse's OAS is clawed back against their own income. US IRMAA and the ACA subsidy still use the household figure. Splitting applies to the deterministic pension income; a discretionary RRIF spending draw is equalized by the per-person allocator instead.
Benefit means-testing beyond what's listed (the Australian Age Pension assets test and Canada's OAS clawback are modelled; for Canada (2026) the Canada Child Benefit and the Guaranteed Income Supplement are modelled — CCB while any child is under 18, GIS for OAS recipients with TFSA withdrawals correctly excluded from the GIS income test; most other countries' means tests are not). Simplified: the GIS clawback tiers are approximated as a flat 50¢/$1 (single) / 25¢/$1 each (couple); GST/HST credit, the Canada Workers Benefit, the 60–64 Allowance, and sponsored-immigrant GIS restrictions are not modelled.
Canada 2026 — further simplifications. Dividend/interest tax during retirement is now split by income type (interest & foreign dividends fully taxable, eligible Canadian dividends grossed-up with the federal + provincial dividend tax credit); not modelled: treaty withholding on foreign dividends, the alternative minimum tax (relevant to large one-year realizations and LCGE claims), LIRA/LIF and per-province unlocking, provincial health premiums (ON) and the RAMQ/QC drug plan, attribution rules / prescribed-rate loans / superficial-loss and capital-loss carryforwards, charitable donation of securities, over-contribution penalties, departure/exit tax on emigration and Part XIII non-resident withholding on a RRIF paid abroad, first-time-buyer land-transfer rebates (a flat transfer % is used), tuition credits and RESP educational-assistance-payment taxation, VRSP/PRPP, the CPP post-retirement benefit, CPP pension sharing (distinct from splitting), CPP survivor/disability benefits and the child-rearing/general dropouts (the estimator assumes a full career), the s.87 Indian Act exemption, and pre-arrival cost basis (deemed acquisition at fair market value on immigration — balances are entered as current values). Provincial age-amount phase-out thresholds mirror the federal figure.
Canadian corporations & rentals (2026). An incorporated professional's CCPC is modelled as a passive-investment container (provincial passive-income rate, CDA and a single RDTOH pool, non-eligible dividend distributions, the $1,275,000 lifetime capital gains exemption on a business sale); not modelled: the small-business-deduction passive-income grind, GRIP / eligible corporate dividends, the eRDTOH/neRDTOH split, salary-vs-dividend optimization while working, and corporation-owned rentals (hold rentals personally). Personally-held rental property assumes no capital cost allowance is claimed (so no recapture on sale — a common conservative filing choice). Corporate distributions are priced against your pension/rental income but not your registered-account withdrawals (so their marginal rate and OAS-clawback effect are slightly understated), and they are not counted in the GIS/Child-Benefit income test.
United States 2026 — what's modelled and what isn't. Modelled: all 50 states + DC with their 2026 income brackets/rates and standard deductions, and each state's retirement-income treatment — states that broadly exempt pensions/IRA/401(k) income (PA, IL, MS…), age/amount-based exclusions (GA, NY, CO…), and the ~8 states that still tax Social Security; the OBBBA $6,000 senior deduction (65+, phased out, current-law sunset after 2028); the Child Tax Credit ($2,200/child under 17, phased out); FICA/self-employment payroll (above); step-up in basis at death (unrealized gains are not taxed to heirs). local/municipal income tax on retirement income for the jurisdictions that levy it — New York City and Yonkers, Maryland's county "piggyback" tax, and the Portland-metro income taxes (each following its state's base and pension exclusion); wage-only city taxes (Philadelphia, Ohio cities, Detroit, St Louis/Kansas City, Kentucky occupational) are correctly treated as not taxing retirement income. Washington's capital-gains excise (7% on realized long-term gains above the ~$278k annual deduction, +2.9% over $1M) and state estate taxes in the 13 jurisdictions that levy them (Oregon $1M and Massachusetts $2M exemptions are the FIRE-relevant ones; applied at death at the state's top marginal rate — an upper bound, since the graduated lower brackets aren't modelled). The HSA as a real triple-tax-advantaged account: contributions deduct federally (up to the $4,400 self / $8,750 family limit + $1,000 catch-up at 55), growth is untaxed, and withdrawals cover your modelled retirement healthcare costs tax-free — tracked as a side-ledger that doesn't inflate the FIRE number. The 529 education account the same way: post-tax contributions grow tax-free and pay a modelled child's education costs tax-free (a side-ledger, excluded from the FIRE number). Tax-free income streams — tag a pension/income row as tax-free (VA disability compensation, workers' comp) and it is received as spendable cash but excluded from taxable income and from every income test (ACA subsidy, IRMAA, Social Security provisional income, benefit phase-outs). Not yet modelled: the EITC, the Medicaid pre-65 coverage floor, HSA CA/NJ non-conformity (those two states don't allow the deduction) and non-medical HSA withdrawals (post-65 ordinary income / pre-65 20% penalty — a well-planned HSA is spent on healthcare, so these are disclosed rather than modelled), local income tax on wages during accumulation (the wage-only city taxes above apply while you're working), state inheritance taxes (they mostly hit siblings/non-relatives, not the spouse/children a plan usually leaves to), the 529 state contribution deduction and non-qualified-withdrawal penalty (10% + earnings tax — a well-planned 529 is spent on education, so these are disclosed), the self-employment-tax deduction and QBI, the IRMAA two-year lookback, the 457(b) plan's penalty-free-on-separation early access (governmental 457(b) money maps to the generic deferred bucket), and Puerto Rico & the territories (a different federal system — not modelled). WEP/GPO were repealed (Social Security Fairness Act) and are correctly modelled as nothing. Two state figures remain flagged for a second-source check in our internal register (North Dakota's exact 2026 bracket breakpoints and Washington's 2026 capital-gains-excise deduction — both not yet published); AMT and the SALT cap are not modelled (standard deduction only).
Category-specific inflation beyond healthcare and education — healthcare and education funds can each be set to rise faster than CPI (a medical-inflation / tuition-inflation premium that compounds to the year the cost lands); housing, cars and other categories still move with the single inflation rate.
Sequence-of-returns within a year (annual steps), taxes on death mid-plan (estate tax applies at the horizon), and divorce/inheritance events (model windfalls as one-offs).

Data freshness & corrections

Every bracket, limit and rate lives in one reviewable data file (countries.js) with per-country tax-year stamps, and 240+ automated invariants run against the engine — including hand-derived tax vectors for every country, each audited against official figures. If you find a number that's wrong for your country, it's a data fix, not a rewrite; the maintenance playbook (UPDATING.md) documents the exact annual refresh procedure and the encoding rules.

Spotted a number that's wrong for your country, or something missing? Send feedback →

Estimates for education only — not financial, tax, or legal advice. Verify important numbers with your tax authority or a licensed professional before acting.