Guides · 高額療養費 · kōgaku ryōyōhi

The Cap on Your Medical Bills — Japan's High-Cost Medical Expense Benefit

By Dr. Masa · physician licensed in Japan · Last reviewed August 2026

If you take one thing from this site, take this: in Japan, there is a monthly ceiling on what you personally pay for insured medical care, no matter how expensive your treatment is. Surgery, cancer treatment, a month in intensive care — your share stops at a figure that, for most working people, is under ¥90,000 for that month.

This is the kōgaku ryōyōhi (高額療養費) system, and it applies to everyone enrolled in Japanese public health insurance, foreign residents included. Many people discover it only after a hospital admission has already frightened them.

Note: the figures below reflect the revision that took effect in August 2026. The caps were raised across all income brackets, and a new annual ceiling was introduced. Most English-language sources still quote the older numbers.

How it works

You normally pay 30% of your medical costs at the counter. The high-cost benefit puts a cap on that 30% share, calculated per calendar month, per person. Anything above the cap is either waived at the hospital (if you have an eligibility certificate) or refunded to you later.

The monthly ceiling, from August 2026 (under age 70)

A worked example. You are in the ¥3.7m–¥7.7m bracket and need surgery. The total billed cost of your care that month is ¥1,000,000. Your 30% share would be ¥300,000. Instead:

¥85,800 + 1% × (¥1,000,000 − ¥286,000) = ¥85,800 + ¥7,140 = ¥92,940

That is your total out-of-pocket for insured care that month.

What changed in August 2026

Every bracket went up. For the middle bracket, the base figure rose from ¥80,100 to ¥85,800; the top bracket rose from ¥252,600 to ¥270,300. A further step of increases is scheduled for 2027.

In exchange, a genuinely useful addition arrived: an annual ceiling, counted over the twelve months from August to the following July. For the middle income bracket this sits at roughly ¥530,000 per year. If you have a long illness that pushes you over the monthly cap repeatedly, the annual figure limits the total damage. Amounts above it are refunded.

The multiple-occurrence reduction (多数回該当) also survives unchanged: if you hit the monthly cap three times within twelve months, your ceiling drops for the fourth and subsequent months.

Get the certificate before you are admitted

There are two ways to benefit, and one is much better than the other.

The good way — 限度額適用認定証 (gendogaku tekiyō ninteishō), the eligibility certificate. Apply to your insurer before a planned admission or expensive treatment. Show it at the hospital counter, and you are simply never charged more than your ceiling. No large payment, no waiting for a refund.

If you have registered your My Number card as your health insurance card, hospitals with the electronic system can usually verify your bracket directly, and no paper certificate is needed. Ask the hospital's reception (医事課) whether they can confirm your 限度額 electronically.

The slower way — claim a refund afterwards. If you have already paid, apply to your insurer for reimbursement. It works, but the money comes back roughly three months later, and you must front the full amount in the meantime. The right to claim expires two years from the end of the month of treatment — if you had a costly month in the past two years and never claimed, it may not be too late.

Where to apply depends on your insurance:

• Employees (健康保険) — your health insurance society (健康保険組合) or the Japan Health Insurance Association (協会けんぽ). Your HR department will know which.
• National Health Insurance (国民健康保険) — the insurance section of your city or ward office.

The important exclusions

The cap applies only to insured medical care. It does not cover:

• The hospital room surcharge for a private or semi-private room (差額ベッド代). This is optional in principle — you are entitled to a standard room, and you should not be charged if you did not consent in writing. Ask before you sign anything on admission.
• Meals during admission (a fixed daily charge).
• Fully self-paid treatment (自由診療), including most advanced or unapproved therapies.
• Anything cosmetic, and normal childbirth (which has its own separate lump-sum benefit).

Costs are also counted per person and per calendar month. A treatment spanning the end of one month and the start of the next is counted as two separate months — which is occasionally worth discussing with your doctor when scheduling something elective. Within a single household, smaller bills can sometimes be combined (世帯合算), with conditions that vary by insurer.

If you are not enrolled

This benefit requires enrolment in public health insurance. If you are a resident of Japan, enrolment is a legal requirement, not an option — and this system is the main reason it is worth complying promptly rather than eventually. Travellers and short-term visitors are not covered and should carry travel insurance.

Figures verified against the revision effective August 2026. Insurance rules are revised regularly; confirm current figures with your own insurer before relying on them for a major decision.