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Original researchThe same $1.2M retirement, modelled in four countries
We took one retirement plan and ran it, month by month to age 90, as a tax resident of the United States, United Kingdom, Canada and Australia. Same savings, same withdrawals, same Social Security — only the tax system and the healthcare bill change.
Download the full dataset → — free, CC BY 4.0.
Three things the numbers say
The order changes
The country that is best the year you retire is often not the one that is best at 80. In the base case the United States climbs from 3rd to 2nd, and Australia slips from 2nd to 3rd, without either of them doing anything differently.
After 67, tax stops being the story
Once Social Security starts, the UK resident's total tax bill converges on the US figure exactly. Everything the UK is still winning by from that point is healthcare, not tax.
It depends how much you have
At $600k Australia starts ahead. At $2.5M the United States does. The UK finishes ahead in every single case we ran — but it is not always in front at the start.
The plan we modelled
A single filer retiring at 60 with $1,200,000 — $800,000 in a 401(k), $300,000 in a taxable brokerage account and $100,000 in cash — drawing $7,000 a month across the three, and claiming $2,800/month of Social Security at 67. Once Social Security starts, portfolio withdrawals are trimmed by what it replaces, so total income stays level rather than stepping up.
The plan is then run four times. The only thing that changes is where the person is tax resident. Phase boundaries land on the events that actually change the arithmetic: Medicare at 65, the Social Security claim at 67, Required Minimum Distributions at 73, and 80.
Net monthly income, by country and age
| Age | United Kingdom | United States | Australia | Canada |
|---|---|---|---|---|
| 60–65 | $6,368 | $6,176 | $6,352 | $6,152 |
| 65–67 | $6,314 | $6,128 | $6,298 | $6,080 |
| 67–73 | $6,749 | $6,437 | $6,098 | $5,928 |
| 73–80 | $6,755 | $6,378 | $6,105 | $5,855 |
| 80–90 | $7,641 | $7,155 | $7,020 | $6,625 |
Net monthly income in US dollars, nominal. Australia is ahead of the US for the first seven years and behind it for the next twenty-three.
Why the order changes
The interesting part is not that the UK leads. It is what it leads with, and how that changes at 67.
Income tax, per month
| Age | United States | United Kingdom | Australia | Canada |
|---|---|---|---|---|
| 60–65 | $367 | $632 | $648 | $848 |
| 65–67 | $373 | $686 | $702 | $920 |
| 67–73 | $361 | $361 | $1,012 | $1,182 |
| 73–80 | $377 | $377 | $1,028 | $1,277 |
| 80–90 | $359 | $359 | $980 | $1,375 |
Before 65, the UK resident pays more income tax than the American — and still comes out ahead. $632 against $367. What settles it is the other column: the American is buying insurance on the ACA marketplace at $457/month, and the UK resident is not. The tax gap is $265; the healthcare gap is $457.
From 67, the two tax bills become identical to the dollar. That is not a coincidence and it is not a rounding artefact. Under the US–UK treaty, US Social Security is taxable only in the UK, while 401(k) withdrawals stay taxable in both — and the Foreign Tax Credit then offsets the US bill by whatever the UK charged. Once the UK's own liability falls below the US liability, the credit stops being able to absorb all of it, and the total you pay settles at the higher of the two figures. Which is the American's.
So from 67 onwards, the UK's entire remaining advantage is healthcare. Not tax policy, not the treaty — the fact that one of these four people is paying Medicare Part B, Part D and an IRMAA surcharge, and the other three are not. That is worth $312–$486 a month in this plan, and it is the single largest cross-border variable in the whole model.
Canada is behind from the first year and falls further every phase — $848/month of tax at 60 becoming $1,375 by 80, because Canadian tax applies to the full 401(k) withdrawal and to Social Security, with no treaty carve-out of the kind the UK gets. Australia starts well, on the strength of its tax-free threshold, and then loses ground once Social Security lands and is taxed as ordinary income.
Does it depend on how much you have? Yes.
We re-ran the whole thing across portfolio sizes, scaling withdrawals with the balance. The ranking in the first phase changes three times:
| Portfolio | Ahead at 60–65 | Ahead at 80–90 |
|---|---|---|
| $600k | Australia › UK › US › Canada | UK › Australia › US › Canada |
| $900k | Australia › UK › US › Canada | UK › US › Australia › Canada |
| $1.2M | UK › Australia › US › Canada | UK › US › Australia › Canada |
| $1.8M | UK › US › Australia › Canada | UK › US › Australia › Canada |
| $2.5M | US › Canada › UK › Australia | UK › US › Canada › Australia |
Three different countries lead at the start depending on the size of the pot — Australia when it is small, the UK in the middle, the United States when it is large. At $2.5M the American is drawing enough that healthcare is a small fraction of income and the US brackets look favourable; at $600k, Australia's tax-free threshold shelters most of a modest income.
The last phase never changes. The UK finishes first at every portfolio size we tested.
Retiring later doesn't reorder it — it just widens the gap
Retiring at 60, 62, 65 or 67 produces the same ordering in both the first and last phase. What changes is the size of the difference: the spread between best and worst country grows from about $205/month at the start to roughly $1,100/month by the eighties. Whatever the decision is worth on the day you make it, it is worth about five times that later.
How this was produced
Every figure comes from the same calculation engine that powers the paid AI Retirement Income Planner and the free Retire Abroad comparison tool — not a spreadsheet approximation built for this article. Income is simulated month by month and averaged over each phase.
The generating script refuses to publish numbers it cannot stand behind: it re-derives a documented twenty-value cross-check against the paid planner before writing any output, and asserts the engine's own identity — net income equals gross minus tax minus healthcare — on every phase of every country.
What is modelled
- US federal income tax — brackets, standard and senior deductions, the taxable-Social-Security calculation, capital gains, NIIT.
- US healthcare — ACA premiums and the subsidy cliff before 65, then Medicare Part B/D and IRMAA surcharges.
- UK personal allowance and rates, the Article 17 treatment of Social Security, and the Foreign Tax Credit.
- Canadian federal brackets, the basic personal amount and a provincial rate.
- Australian tax-free threshold, marginal rates and the Medicare levy.
- Required Minimum Distributions from 73, on the IRS Uniform Lifetime Table.
- Inflation on brackets, deductions, thresholds and healthcare costs, per phase.
What is not — read this before quoting it
- No healthcare cost outside the US. The UK, Canadian and Australian figures assume the public system covers you at no direct premium. Since healthcare turns out to be the largest single lever here, this assumption is doing a great deal of work. Private cover, an insurance requirement attached to a visa, or a surcharge for new residents would all reduce those columns.
- US state income tax is set to zero — a no-tax state. That flatters the US column, so any overseas advantage shown is understated.
- No local social-security entitlements — no CPP, OAS, Age Pension or UK State Pension. This compares the same savings under different tax systems, not different working lives.
- Nominal dollars, not inflation-adjusted, and no currency risk — everything is priced in USD.
- Nothing about visas, residency eligibility or domicile. Being allowed to live somewhere is a separate question from what it would cost you.
- Retirement ages below 60 are excluded. Before 59½ a 401(k) is effectively locked, and the model opens a phase where almost nothing can be drawn — identical in all four countries, so there is nothing to compare. Bridging that gap needs a taxable account, a Roth ladder or a 72(t), which is a different study.
Take the data
Free to use with attribution (CC BY 4.0). If you are writing about cross-border retirement, a link back to this page is all we ask.
Base case (CSV) Full study incl. grids (JSON)
The CSV carries net income, income tax and healthcare cost per country per phase. The JSON adds the retirement-age and portfolio-size grids and the exact inputs used.
Run it with your own numbers
The comparison tool is free, needs no sign-up and does not ask for your email. Put your own balances and withdrawals in and see where you land.
This is an educational model, not financial, tax or legal advice, and not a personalised recommendation. Every figure is an estimate produced from the stated assumptions. Cross-border tax is genuinely complicated — treaty position, domicile and residency tests can all change the answer. Talk to a qualified cross-border adviser before acting on any of it.