How Much Does Health Insurance Cost in Japan? — Full Simulations by Income & City
"How much will I actually pay for insurance?" is the question every foreign resident in Japan asks — and the answer is frustratingly variable. Your premium depends on which system you're in (NHI or Shakai Hoken), where you live, how much you earn, how many family members are on your plan, and whether you're over 40.
The same person earning ¥4 million a year could pay ¥283,000 on NHI in Tokyo's 23 wards — or ¥316,000 in Osaka. On Shakai Hoken in Tokyo, the health insurance portion alone would be ¥200,000, with the employer covering an equal amount. Add a spouse and child, and the NHI bill jumps by ¥120,000 while Shakai Hoken stays flat.
This article runs the numbers across 5 income levels × 5 major cities, then covers the High-Cost Medical Benefit caps, first-year-in-Japan pricing, the age 40+ nursing care surcharge, National Pension costs, and the real impact on your take-home pay.
→ Part of the Health Insurance in Japan series. For system details: ② NHI Guide and ③ Shakai Hoken Guide.
How NHI Premiums Are Calculated — Quick Recap
NHI premiums consist of three components:
① Medical portion (基礎賦課分): Income-based levy (assessment base × rate) + per-capita levy (fixed amount per enrollee). Annual cap: ¥690,000 (2025).
② Elderly Support portion (後期高齢者支援金分): Income-based + per-capita levies. Cap: ¥240,000.
③ Nursing Care portion (介護分, ages 40–64 only): Income-based + per-capita levies. Cap: ¥170,000.
Assessment base = Previous year's total income − ¥430,000 basic deduction.
2025 maximum total = ¥690K + ¥240K + ¥170K = ¥1,100,000 (with nursing care) / ¥930,000 (without).
Rates and per-capita amounts vary by municipality — which is why the same income produces different premiums in different cities.
NHI Premium Simulations: 5 Incomes × 5 Cities (Single, Under 40)
All simulations assume: salaried income, single household, age under 40 (no nursing care levy).
Converting Salary to Assessment Base
| Annual salary | Income after deduction | Assessment base (income − ¥430K) |
|---|---|---|
| ¥2,000,000 | ¥1,320,000 | ¥890,000 |
| ¥3,000,000 | ¥2,020,000 | ¥1,590,000 |
| ¥4,000,000 | ¥2,760,000 | ¥2,330,000 |
| ¥5,000,000 | ¥3,560,000 | ¥3,130,000 |
| ¥6,000,000 | ¥4,360,000 | ¥3,930,000 |
| ¥8,000,000 | ¥6,100,000 | ¥5,670,000 |
Annual NHI Premiums by City (Approximate)
| Income | Tokyo 23 Wards | Osaka | Nagoya | Fukuoka | Sapporo |
|---|---|---|---|---|---|
| ¥2M | ~¥145,000 | ~¥153,000 | ~¥143,000 | ~¥144,000 | ~¥152,000 |
| ¥3M | ~¥212,000 | ~¥232,000 | ~¥216,000 | ~¥221,000 | ~¥228,000 |
| ¥4M | ~¥283,000 | ~¥316,000 | ~¥293,000 | ~¥305,000 | ~¥312,000 |
| ¥5M | ~¥360,000 | ~¥406,000 | ~¥376,000 | ~¥395,000 | ~¥401,000 |
| ¥6M | ~¥436,000 | ~¥496,000 | ~¥459,000 | ~¥484,000 | ~¥490,000 |
| ¥8M | ~¥603,000 | ~¥693,000 | ~¥639,000 | ~¥679,000 | ~¥680,000 |
At ¥2M income, the city-to-city difference is roughly ¥10,000/year. But at ¥8M, the gap between Tokyo 23 wards and Osaka stretches to approximately ¥90,000/year. Tokyo's relatively lower income-based rate makes it more favorable at higher income levels.
The Age 40+ Surcharge: Nursing Care Insurance
NHI enrollees aged 40–64 pay an additional nursing care levy (介護分). At ¥4M income in Tokyo 23 wards, this adds approximately ¥78,000/year — pushing the total from ~¥283,000 to ~¥361,000.
Shakai Hoken Premiums: The Employer-Split Advantage
Shakai Hoken uses a nationally standardized calculation, but Kyokai Kenpo health insurance rates differ by prefecture.
2025 Kyokai Kenpo Health Insurance Rates
| Prefecture | Total rate | Employee share (÷2) |
|---|---|---|
| Tokyo | 9.80% | 4.90% |
| Osaka | 10.22% | 5.11% |
| Aichi (Nagoya) | 9.93% | 4.965% |
| Fukuoka | 10.35% | 5.175% |
| Hokkaido (Sapporo) | 10.29% | 5.145% |
Employees' Pension rate: Nationally uniform at 18.3% (employee pays 9.15%).
Monthly Premiums — Employee Share Only (Tokyo)
| Income | Monthly salary | Standard Monthly Remuneration | Health ins. | Pension | Total |
|---|---|---|---|---|---|
| ¥2M | ¥166,667 | ¥170,000 | ¥8,330 | ¥15,555 | ¥23,885 |
| ¥3M | ¥250,000 | ¥260,000 | ¥12,740 | ¥23,790 | ¥36,530 |
| ¥4M | ¥333,333 | ¥340,000 | ¥16,660 | ¥31,110 | ¥47,770 |
| ¥5M | ¥416,667 | ¥410,000 | ¥20,090 | ¥37,515 | ¥57,605 |
| ¥6M | ¥500,000 | ¥500,000 | ¥24,500 | ¥45,750 | ¥70,250 |
| ¥8M | ¥666,667 | ¥650,000 | ¥31,850 | ¥59,475 | ¥91,325 |
Head-to-Head: Annual Health Insurance Cost Only
| Income | Shakai Hoken (Tokyo, health only) | NHI (Tokyo 23 wards) | NHI costs more by |
|---|---|---|---|
| ¥2M | ¥99,960 | ¥145,000 | +¥45,000 |
| ¥3M | ¥152,880 | ¥212,000 | +¥59,000 |
| ¥4M | ¥199,920 | ¥283,000 | +¥83,000 |
| ¥5M | ¥241,080 | ¥360,000 | +¥119,000 |
| ¥6M | ¥294,000 | ¥436,000 | +¥142,000 |
| ¥8M | ¥382,200 | ¥603,000 | +¥221,000 |
NHI costs more at every income level — and Shakai Hoken includes benefits (income replacement, maternity pay, free dependent coverage) that NHI doesn't. The cost comparison isn't even close once you factor in what you're getting.
→ Benefit comparison details in ④ NHI vs Shakai Hoken vs Private
Adding Family Members: Where the Gap Explodes
NHI: Each person adds to the bill
At ¥4M income in Tokyo 23 wards:
| Household | Annual NHI (approx.) |
|---|---|
| Single | ~¥283,000 |
| Couple (spouse, no income) | ~¥343,000 |
| Couple + 1 child | ~¥403,000 |
| Couple + 2 children | ~¥463,000 |
Each additional person adds approximately ¥60,000/year in per-capita levies — regardless of their income.
Shakai Hoken: Dependents are free
If your spouse earns under ¥1.3M/year, they're covered as a dependent at zero additional cost. Children are also free.
At ¥4M income, couple + 2 children: Shakai Hoken (health only): ~¥200,000/year (same as single) NHI (Tokyo): ~¥463,000/year
Annual difference: approximately ¥263,000 — about ¥22,000 per month more on NHI.
First Year in Japan: Temporarily Low NHI, Normal Shakai Hoken
NHI: Previous-year income = zero → minimal premium
NHI bases premiums on your previous year's income in Japan. If you arrived this year with no prior Japanese income, the income-based levy is zero. With the 70% statutory reduction applied:
Tokyo 23 wards: Per-capita levies ¥60,100 × 0.3 = approximately ¥18,000/year (¥1,500/month)
This is extremely cheap — but it's a one-time windfall. If you earn ¥4M in your first year, your second-year NHI premium jumps to ~¥283,000. Budget accordingly.
Shakai Hoken: Full premium from month one
Shakai Hoken bases premiums on your current salary, so there's no first-year discount. From your very first paycheck, full health insurance and pension premiums are deducted.
High-Cost Medical Benefit: Your Safety Net for Big Bills
Both NHI and Shakai Hoken apply the same High-Cost Medical Benefit (高額療養費) system. When your medical bills in a single month exceed a threshold, the excess is covered — your out-of-pocket is capped.
Monthly Caps by Income Tier (Under 70)
| Tier | Income guideline | Monthly cap formula | Approximate cap |
|---|---|---|---|
| A | Income ~¥11.6M+ | ¥252,600 + (total cost − ¥842,000) × 1% | ~¥250,000+ |
| B | ~¥7.7M–11.6M | ¥167,400 + (total cost − ¥558,000) × 1% | ~¥170,000+ |
| C | ~¥3.7M–7.7M | ¥80,100 + (total cost − ¥267,000) × 1% | ~¥80,000–90,000 |
| D | ~¥3.7M or below | ¥57,600 flat | ¥57,600 |
| E | Tax-exempt | ¥35,400 flat | ¥35,400 |
Example: ¥4M income, surgery costing ¥1,000,000 total
Tier C applies: Cap = ¥80,100 + (¥1,000,000 − ¥267,000) × 1% = ¥80,100 + ¥7,330 = ¥87,430
Instead of ¥300,000 at 30% copay, you pay ¥87,430. If you hit the cap 3 times in 12 months, the 4th month onward drops to ¥44,400.
Critical note: If you haven't filed an income declaration, your tier may default to the most expensive bracket (Tier A) — meaning you'd pay up to ¥252,600+ instead of ¥87,430. File your zero-income declaration.
National Pension: The Other Fixed Cost for NHI Enrollees
NHI covers health insurance only. If you're on NHI, you also owe National Pension (国民年金) premiums separately (ages 20–59).
2025 National Pension premium: ¥17,510/month (¥210,120/year)
This is a flat amount regardless of income. Combined with NHI:
| Income | NHI (Tokyo) | National Pension | Combined annual | Monthly |
|---|---|---|---|---|
| ¥2M | ¥145,000 | ¥210,120 | ¥355,120 | ¥29,593 |
| ¥3M | ¥212,000 | ¥210,120 | ¥422,120 | ¥35,177 |
| ¥4M | ¥283,000 | ¥210,120 | ¥493,120 | ¥41,093 |
| ¥5M | ¥360,000 | ¥210,120 | ¥570,120 | ¥47,510 |
Shakai Hoken enrollees don't pay National Pension separately — it's included in the Employees' Pension deduction.
Take-Home Pay Impact: NHI vs Shakai Hoken (¥4M, Single, Tokyo, Under 40)
| Item | Shakai Hoken (Employee) | NHI (Freelancer) |
|---|---|---|
| Gross income | ¥4,000,000 | ¥4,000,000 |
| Health insurance / NHI | −¥199,920 | −¥283,000 |
| Pension (Employees' / National) | −¥373,320 | −¥210,120 |
| Employment insurance (0.55%) | −¥22,000 | — |
| Income tax + resident tax (est.) | −~¥208,000 | −~¥245,000 |
| Take-home (est.) | ~¥3,197,000 | ~¥3,262,000 |
The freelancer appears to keep slightly more — but this is deceptive. The freelancer has no unemployment insurance (no safety net if work dries up), a lower future pension (National Pension pays less than Employees' Pension), no Injury & Sickness Allowance, no Maternity Allowance, and no free dependent coverage.
When you factor in the value of what you're getting, Shakai Hoken is overwhelmingly more cost-effective. This is the core message throughout this series.
Statutory Reductions: Significant Savings for Low-Income Enrollees
NHI per-capita levies are reduced by 70%, 50%, or 20% when household income falls below certain thresholds.
2025 Reduction Thresholds (Single Household)
| Reduction | Household income ceiling | Per-capita payment (Tokyo 23 wards) |
|---|---|---|
| 70% reduction | ¥430,000 or below (basic deduction only) | ¥60,100 × 0.3 = ¥18,030 |
| 50% reduction | ¥430K + ¥295K × enrollees | ¥60,100 × 0.5 = ¥30,050 |
| 20% reduction | ¥430K + ¥545K × enrollees | ¥60,100 × 0.8 = ¥48,080 |
| No reduction | Above thresholds | ¥60,100 |
Eligible scenarios: First year in Japan (zero prior income), students with limited part-time income, recently unemployed (applies from the following fiscal year).
The catch: You must have filed an income declaration for the reduction to apply. No declaration = no reduction = higher premiums. Even zero income requires a declaration.
The Full Cost Picture
| Situation | Approximate annual cost (Tokyo, under 40) |
|---|---|
| First year, NHI, zero income | ~¥18,000 (70% reduction) |
| Student, NHI, ¥1M income | ~¥60,000–80,000 |
| Freelancer, NHI, ¥3M (+ National Pension) | ~¥422,000 |
| Freelancer, NHI, ¥5M (+ National Pension) | ~¥570,000 |
| Employee, Shakai Hoken, ¥3M (health only, employee share) | ~¥153,000 |
| Employee, Shakai Hoken, ¥5M (health only, employee share) | ~¥241,000 |
| NHI, ¥4M, couple + 1 child (Tokyo) | ~¥403,000 |
| Shakai Hoken, ¥4M, couple + 1 child (Tokyo) | ~¥200,000 (dependents free) |
Three essential takeaways:
① Shakai Hoken is more cost-efficient at every income level and family size — and includes superior benefits. ② NHI enrollees face combined social insurance costs (NHI + National Pension) of ¥400,000–650,000 per year. ③ Failing to file an income declaration (even a zero-income one) costs you in three ways: no premium reductions, unfavorable High-Cost Medical Benefit tier, and 2027 visa compliance risk.
Navigate the Full Series
| Article | What it covers |
|---|---|
| ① Complete Guide (Hub) | Full system overview |
| ② NHI Deep Dive | Enrollment, premiums, reductions, zero-income declaration |
| ③ Shakai Hoken | Employer insurance details |
| ④ Comparison | NHI vs Shakai Hoken vs private |
| ⑤ Seeing a Doctor | Hospital navigation, English support |
| ⑥ 2027 Rule | Visa enforcement details |
| ⑧ Leaving Japan | Disenrollment, refunds |
| ⑨ Having a Baby | Childbirth coverage |
All simulations in this article are approximate. Actual premiums depend on your municipality's current-year rates, which are revised annually. For precise calculations, consult your municipal NHI office or use your city's online premium calculator. Content is current as of February 2026.
Health insurance costs are one of those things that vary wildly from country to country — and often surprise people when they move. How do Japan's premiums compare to what you paid back home? Is it more or less than you expected? And for those on NHI — has the cost been manageable, or did the second-year jump catch you off guard? Share your numbers and experience.