NHI Premiums Explained: How Your Rate Is Calculated
National Health Insurance premiums in Japan are not a flat fee. They are calculated based on your previous year's income, the number of household members enrolled, and a per-household flat rate. Understanding this formula can help you budget accurately and identify whether you qualify for reductions.
| Component | Basis | Typical Range |
|---|---|---|
| Income-based (所得割) | Previous year taxable income | 6–10% of income |
| Per-capita (均等割) | Number of enrolled members | 30,000–50,000 yen/person/year |
| Household flat (平等割) | Per household | 20,000–40,000 yen/year |
| Asset-based (資産割) | Property tax amount (some cities) | Varies |
How the Calculation Works
First Year in Japan
If you had no income in Japan the previous year, your premium may be quite low — sometimes just the per-capita and household components. However, some municipalities may request documentation of overseas income.
Subsequent Years
Once you file a tax return in Japan, your income-based component kicks in. Higher earners pay significantly more, with an annual cap (typically around 1,020,000 yen for the combined medical + support + nursing portions).
Premium Reductions
Low-income households may qualify for 70%, 50%, or 20% reductions on the per-capita and household portions. Filing a tax return — even with zero income — is important to trigger these reductions automatically.
Payment Methods
- Convenience store (with payment slip)
- Bank automatic deduction
- Credit card (some municipalities)
- Bank/post office counter
Q: Why is my premium higher than my friend's in a different city?
NHI premium rates vary by municipality. Each city sets its own rates based on local healthcare costs and financial reserves. Two people with identical incomes may pay different amounts in different cities.
Q: What happens if I cannot pay?
Contact your city office's insurance division to discuss payment plans or hardship exemptions. Ignoring premium notices can result in a short-term insurance certificate or benefit restrictions.
※ This article is for informational purposes only. Premium rates vary by municipality and fiscal year. Please confirm your rate at your local city office.
