National Health Insurance (NHI) premiums can differ by more than ¥100,000 a year depending on which municipality you live in. Unlike employer-based health insurance, NHI rates are set individually by each municipality. Using one identical model case — a 40-year-old single person with ¥4 million a year in salary income — we have independently estimated and ranked NHI premiums for 212 municipalities across the four Greater Tokyo prefectures. This article is the gateway to those rankings: links to the detailed ranking for each prefecture, the cheapest and most expensive municipalities across the region, why the gaps arise, and how to lower your premium without moving.
(1) Even for the same ¥4 million salary and 40-year-old single person, NHI premiums in the Greater Tokyo area range roughly from ¥280,000 to ¥430,000 a year.
(2) Within each prefecture the largest gap is ¥100,000–140,000 a year. Tokyo's 23 wards use a unified premium system, but Nakano Ward alone sets its own rates and is the most expensive.
(3) Some municipalities in the same commuting area differ by more than ¥60,000 a year, such as Chiba City and Funabashi City.
(4) Even without moving, you may be able to pay less just by understanding how the premium is calculated and checking the reductions and exemptions.
Detailed Rankings by Prefecture (4 Published, More Coming)
The full municipal ranking, the rate breakdown and the reduction rules for each prefecture are explained in the individual articles. The Tokyo article also includes a simulator that calculates all 62 municipalities at once from your income, age and household makeup.
Now available: Tokyo (62 municipalities), Saitama (63 municipalities), Chiba (54 municipalities) and Kanagawa (33 municipalities)
Other prefectures will be added in due course.
Cheapest and Most Expensive in the Four Prefectures at a Glance
The table shows the cheapest and most expensive municipality in each prefecture under the model case (40-year-old single person, ¥4 million salary income). Note that Tokyo, Saitama and Kanagawa use FY2026 rates while Chiba uses FY2025 rates, so strict comparisons across prefectures carry a fiscal-year gap.
| Prefecture (municipalities) | Cheapest | Most expensive | Gap |
|---|---|---|---|
| Tokyo (62) | Mikurajima Village ¥154,857 Cheapest among cities: Fuchu City ¥276,645 | Nakano Ward ¥404,914 | About ¥130,000/yr (vs. cities) |
| Saitama (63) | Kawajima Town ¥311,840 | Tokorozawa City ¥418,577 | About ¥107,000/yr |
| Chiba (54) | Onjuku Town ¥288,350 | Mutsuzawa Town ¥427,830 | About ¥139,000/yr |
| Kanagawa (33) | Nakai Town ¥294,929 | Hadano City ¥422,274 | About ¥127,000/yr |
Note: the Tokyo, Saitama and Kanagawa figures include the child and childcare support portion added from FY2026, while the Chiba figures (FY2025 rates) do not. We will replace the numbers, together with each individual article, as the new fiscal-year rates are published.
Three Patterns That Emerge Across the Prefectures
- "Suburban towns and villages are cheaper" does not always hold. In Chiba, the cheapest and the most expensive are both towns (Onjuku Town and Mutsuzawa Town), and in Saitama, commuter cities close to central Tokyo such as Toda City and Wako City rank among the cheapest. Land prices and convenience do not track NHI premiums.
- Big-city centers are not necessarily the most expensive either. Yokohama City ranks 27th of Kanagawa's 33 municipalities (about ¥401,000), on the expensive side, yet Tokyo's 23 wards sit mid-table under their unified premium system — only Nakano Ward, with its own rate schedule, stands out at the top.
- Neighboring municipalities in the same commuting area can differ by tens of thousands of yen a year. Chiba City (about ¥373,000) and Funabashi City (about ¥310,000) differ by roughly ¥63,000 a year — a textbook case of the premium changing with your city of residence alone, with no change in commuting conditions.
These gaps arise because each municipality independently sets its income-based rate, per-capita levy and per-household levy (a flat amount per household). The calculation structure itself is broken down in our guide to how NHI premiums are calculated. Saitama Prefecture has announced plans to semi-unify rates within the prefecture in FY2027 and fully unify them in FY2030, so municipal gaps there are expected to shrink.
How to Lower Your NHI Premium Without Moving
The rankings show how much your address matters, but moving is not the only remedy.
- Check the statutory reductions and exemptions. If last year's income is below certain thresholds, a 70%, 50% or 20% reduction of the per-capita and per-household levies applies automatically. If you suspect a reduction has been missed, or in cases of job loss or disaster, see how NHI premiums are calculated.
- Right after leaving a job, compare the three options. Besides NHI, you can voluntarily continue your employer plan (nin'i keizoku) or join a family member's plan as a dependent — which is cheapest differs from person to person. Compare them in our guide to the three health insurance options after leaving a job.
- Sole proprietors can also consider incorporating. Depending on your income, switching to employee social insurance through a micro-corporation can lower your total burden (it requires designing your director's salary accordingly).
Frequently Asked Questions
Which municipality in Japan has the highest or lowest NHI premium?
There is no official nationwide ranking that compares every municipality under identical conditions. Each municipality publishes its own rates, so comparison requires estimates on a single model case. We are expanding our estimates (single, age 40, salary 4 million yen) and currently cover 212 municipalities in the Tokyo metropolitan area, where the gap between highest and lowest is roughly 150,000 yen a year.
Do the amounts in the rankings apply to me as they are?
Not directly. Every article uses the same model case — a 40-year-old single person with ¥4 million in salary income — so with a different income, age or household makeup, both the amounts and the order can change. The simulator in the Tokyo article calculates all 62 municipalities under your own conditions. For your exact premium, check with your municipality's office or your premium notice.
If I move to a municipality with cheaper NHI, do I always come out ahead?
Looking at the premium alone, yes, it goes down. But residence tax barely differs between municipalities, and other factors — rent, commuting costs, childcare support — can matter more. It is more realistic to treat the NHI gap as one input among many when choosing where to live, and to compare total living costs.
Why do the articles use different fiscal years?
Because each prefecture publishes its rates at a different time. The Tokyo, Saitama and Kanagawa estimates use FY2026 (Reiwa 8) rates, while Chiba uses FY2025 (Reiwa 7) rates. We will update each article as the new fiscal-year rates become available.
References (Sources)
- Tokyo: Tokyo Metropolitan Bureau of Health and Medical Services — NHI premium amounts by municipality
- Municipal rates for Saitama, Chiba and Kanagawa: listed in the source sections of the individual articles (Saitama, Chiba, Kanagawa)
The amounts in this article are our site's own estimates (model case) based on the rates published by each municipality and may differ from your actual premium. This is general information; for individual decisions, consult the municipality where you live or a professional.
