How Much Does Health Insurance Cost in Japan? Full Simulations by Income

"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.

Take one person earning ¥4 million a year. In Tokyo's Edogawa Ward, their NHI premium for FY2026 is about ¥323,000. On Shakai Hoken, their share of health insurance comes to about ¥206,000, with the employer paying the same again. Add a spouse and a school-age child, and the NHI bill rises by about ¥134,000, while the Shakai Hoken bill doesn't change.

This article runs the numbers for 6 income levels using one municipality's official FY2026 rates, explains how much your own city can differ, and then covers the High-Cost Medical Benefit caps, first-year-in-Japan pricing, the age 40+ nursing care surcharge, National Pension, 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 have these components:

① Medical portion (基礎賦課分): Income-based levy (assessment base × rate) + per-capita levy (fixed amount per enrollee). Annual cap: ¥670,000 (FY2026).

② Elderly Support portion (後期高齢者支援金分): Income-based + per-capita levies. Cap: ¥260,000.

③ Nursing Care portion (介護分, ages 40–64 only): Income-based + per-capita levies. Cap: ¥170,000.

④ Child and child-rearing support portion (子ども・子育て支援納付金分, new from FY2026): Charged to all members (the per-capita part only to those aged 18 and over). Cap: ¥30,000.

Assessment base = previous year's total income − ¥430,000 basic deduction.

FY2026 maximum total = ¥670K + ¥260K + ¥170K + ¥30K = ¥1,130,000 (with nursing care) / ¥960,000 (without).

Rates and per-capita amounts are set by each municipality, which is why the same income produces different premiums in different places.

NHI Premium Simulations by Income (Edogawa Ward, Tokyo, FY2026)

The simulations below use the official FY2026 rates of Tokyo's Edogawa Ward, so every figure can be checked against a published source. They assume employment income, a single-person household, and an age under 40 (no nursing care portion).

Edogawa Ward's FY2026 rates

Annual NHI premium by income

None of these incomes qualifies for a statutory reduction for a single person, so the full per-capita levies apply.

How much your city can differ

Your own premium will not match these figures exactly unless you live in Edogawa. Each municipality sets its own rates every year, and even Tokyo's 23 wards no longer share one rate: in FY2026, Nerima charges 7.51% and ¥47,600 for the medical portion, against Edogawa's 7.83% and ¥48,900. Some cities also add a per-household levy (平等割). At the same income, premiums can differ by tens of thousands of yen a year between municipalities, and the gap tends to widen as income rises.

To get your own figure, search for your city's name together with 国民健康保険料 シミュレーション (NHI premium simulator). Most cities publish one, and your municipal NHI counter can give you an exact estimate.

The Age 40+ Surcharge: Nursing Care Insurance

NHI enrollees aged 40–64 also pay the nursing care portion (介護分). In Edogawa it adds about ¥39,200 a year at ¥2 million of salary, ¥74,500 at ¥4 million and ¥113,700 at ¥6 million. At ¥4 million, the total rises from about ¥323,100 to about ¥397,600.

Shakai Hoken Premiums: The Employer-Split Advantage

Shakai Hoken uses a nationally standardized calculation, but Kyokai Kenpo health insurance rates vary by prefecture.

FY2026 Kyokai Kenpo Health Insurance Rates

Since April 2026, a child and child-rearing support levy of 0.23% (0.115% employee share) is collected on top of these rates.

Employees' Pension rate: Uniform 18.3% nationwide (employee pays 9.15%).

Monthly Premiums: Employee Share Only (Tokyo)

The employee's share is rounded down when the fraction is 50 sen or less.

Head-to-Head: Annual Health Insurance Cost

Both columns include the child and child-rearing support portion, so the comparison is like for like.

NHI costs more at every income level, and Shakai Hoken includes benefits (income replacement, maternity allowance, free dependent coverage) that NHI lacks. The comparison isn't close when you factor in what you're getting.

→ Detailed benefit comparison in ④ NHI vs Shakai Hoken vs Private Insurance

Adding Family Members: Where the Gap Explodes

NHI: Each person adds to the bill

At ¥4 million income in Edogawa (spouse with no income, children aged 6 to 17):

Each additional adult adds ¥68,170 a year in per-capita levies, and each child adds ¥66,300 (children under 18 pay no per-capita child-support levy), regardless of income. Children under 6 get a 50% reduction on per-capita levies.

Shakai Hoken: Dependents are free

If your spouse earns under ¥1.3M/year (¥1.5M for dependents aged 19 to 22 other than a spouse), they're covered as a dependent at no additional cost. Children are also free.

At ¥4 million income, couple + 2 children: Shakai Hoken (health + child levy): about ¥205,600/year (same as single) NHI (Edogawa): about ¥523,800/year

Annual difference: approximately ¥318,000, about ¥26,500 more per month on NHI.

First Year in Japan: Temporarily Low NHI, Normal Shakai Hoken

NHI: Previous-year income = zero → minimal premium

NHI calculates premiums from your previous year's Japanese income. If you arrived this year with no prior Japanese income, the income-based levy is zero. With the 70% statutory reduction:

Edogawa (FY2026): Per-capita levies ¥68,170 × 0.3 = approximately ¥20,450/year (about ¥1,700/month)

That's very cheap, but it's a one-time advantage. If you earn ¥4 million in your first year, your second-year NHI premium jumps to about ¥323,000. Budget accordingly.

Shakai Hoken: Full premium from month one

Shakai Hoken calculates premiums from your current salary, so there's no first-year discount. Full health and pension premiums are deducted from your first paycheck.

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, from August 2026)

The caps rose on August 1, 2026, and the annual cap is new: once your out-of-pocket spending from August through the following July reaches it, you pay nothing more for that period. A second phase in August 2027 will split each tier except E into three narrower brackets.

Example: ¥4M income, surgery costing ¥1,000,000 total

Tier C applies: Cap = ¥85,800 + (¥1,000,000 − ¥286,000) × 1% = ¥85,800 + ¥7,140 = ¥92,940

Instead of ¥300,000 at 30% copay, you pay ¥92,940. 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 ¥270,300+ instead of ¥92,940. 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 must also pay National Pension (国民年金) premiums separately (ages 20–59).

FY2026 National Pension premium: ¥17,920/month (¥215,040/year)

This is a flat rate regardless of income. Combined with NHI (Edogawa):

Shakai Hoken members don't pay National Pension separately: it's included in the Employees' Pension deduction.

Take-Home Pay Impact: NHI vs Shakai Hoken (¥4M, Single, Under 40)

Income tax and resident tax are not included, because they depend on deductions that differ between employees and freelancers.

The freelancer appears to keep about ¥61,000 more, but that's misleading. The freelancer has no employment insurance (no safety net if work dries up), will receive a lower future pension (National Pension pays less than Employees' Pension), and has no sickness allowance, no maternity allowance and no free dependent coverage.

When you factor in the value of what you get, Shakai Hoken is overwhelmingly more cost-effective. This is the core message of this entire 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.

FY2026 Reduction Thresholds (Single Household)

Typical qualifying cases: First year in Japan (no prior income), students with a small part-time income (a ¥1 million salary leaves ¥350,000 of employment income, inside the 70% band), people who recently lost their job (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. Zero-income filers must still declare.

The Full Cost Picture

Three essential takeaways:

① Shakai Hoken is more cost-efficient at every income level and family size, and comes with better benefits. ② NHI enrollees face combined social insurance costs (NHI + National Pension) of roughly ¥380,000 to ¥710,000 per year at incomes of ¥2 to ¥6 million. ③ Not filing an income declaration (even zero income) costs you three ways: no premium reductions, an unfavorable High-Cost Medical Benefit tier, and visa risk under the 2027 rule.

Navigate the Full Series

All NHI simulations in this article use Edogawa Ward's official FY2026 rates. Your premium depends on your own 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 October 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.