Treatment Costing ¥1 Million, Paying About ¥93,000: How Japan’s High-Cost Medical Expense Benefit Changed in August 2026

Under Japan’s public health insurance system, what people under 70 pay at the counter of a hospital or pharmacy is, in principle, 30% of the cost of treatment. When hospitalization, surgery, or expensive medication continues, even 30% can add up to a large amount. To address this, there is a system under which, when the amount paid in a month exceeds a set ceiling, the amount over that ceiling is paid out by the insurance. This is the high-cost medical expense benefit (高額療養費, kōgaku ryōyōhi). The Ministry of Health, Labour and Welfare (MHLW) gives an example for the system that took effect in August 2026: for someone under 70 with an annual income of roughly ¥3,700,000 to ¥5,100,000 who receives ¥1,000,000 worth of treatment, out-of-pocket payment is capped at about ¥93,000.

This ceiling was raised in August 2026, and at the same time a new yearly ceiling (annual cap) was introduced. In August 2027, the income brackets are scheduled to be divided more finely. What follows was confirmed in September 2026 from the text of the Health Insurance Act and the National Health Insurance Act and their enforcement orders (via the e-Gov law search database), and from guidance issued by the Ministry of Health, Labour and Welfare (MHLW) and the Japan Health Insurance Association (全国健康保険協会, Kyōkai Kenpo). This article does not determine which bracket applies to you or how much of a given medical expense will be refunded. That is decided by the insurer of the plan you are enrolled in.

Counted by “One Month” and “One Medical Institution”

The high-cost medical expense benefit is set out in Article 115 of the Health Insurance Act (健康保険法; for employees’ health insurance and similar plans) and Article 57-2 of the National Health Insurance Act (国民健康保険法; for National Health Insurance), with the detailed rules on ceiling amounts and the like set by cabinet order (enforcement order). What is counted is the amount paid at the counter, from the 1st to the last day of the month, for treatment covered by insurance. It does not include the cost of meals during hospitalization, the extra charge for a private or semi-private room, or treatment not covered by insurance. The Guidebook on Living and Working (生活・就労ガイドブック), Japanese edition, 8th edition, February 2026, supervised by the Immigration Services Agency of Japan (ISA), also explains the high-cost medical expense benefit in this way.

According to Kyōkai Kenpo’s guidance, the out-of-pocket amount is calculated separately for each medical institution, and even at the same hospital, “medical inpatient care,” “medical outpatient care,” “dental inpatient care,” and “dental outpatient care” are counted separately. Amounts paid at a pharmacy against a prescription are counted together with the amount for the medical institution that issued that prescription.

Ceiling Amounts for People Under 70 (From August 2026)

The ceiling amount is determined by age (under 70, or 70 and over) and income. For people under 70 there are five brackets. Under employees’ health insurance and similar plans, the bracket is determined by the “standard monthly remuneration” (標準報酬月額), the amount based on salary that forms the basis for calculating premiums.

The ceiling amounts under National Health Insurance are the same. However, the brackets are divided differently: Article 29-3 of the National Health Insurance Act Enforcement Order divides households into five groups based on the combined prior-year income (total income after the basic deduction) of all National Health Insurance enrollees in the household: over ¥9,010,000; over ¥6,000,000 up to ¥9,010,000; over ¥2,100,000 up to ¥6,000,000; ¥2,100,000 or less; and exempt from resident tax.

Here is a worked example. Suppose someone in bracket ウ receives ¥1,000,000 worth of treatment in a month at the same hospital. Their 30% co-payment at the counter is ¥300,000. The ceiling amount is ¥85,800 + 1% × (¥1,000,000 − ¥286,000) = ¥92,940, so the difference between that and ¥300,000 — ¥207,060 — is paid out as the high-cost medical expense benefit. Under the formula used through July 2026, the ceiling amount would have been ¥87,430.

The “Repeat-Month Reduction”: Lower From the Fourth Month

If, within the 12 months before that month, there have already been three or more months in which the high-cost medical expense benefit was paid, the ceiling amount is lowered from the fourth month onward (Health Insurance Act Enforcement Order, Article 42, Paragraph 1). This is called the “repeat-month reduction” (多数回該当, tasūkai gaitō), and it is the amount in the “Repeat-month reduction” column of the table above. Kyōkai Kenpo advises that when the insurer changes (such as moving from National Health Insurance to Kyōkai Kenpo) or when a person switches from being the insured party to being a dependent of a family member, the previous months are not carried over. Under National Health Insurance, if someone moves to a different municipality within the same prefecture, months for which the benefit was paid in the previous municipality are still counted (National Health Insurance Act Enforcement Order, Article 29-3, Paragraph 1).

Combining Family Members’ Payments: “Household Aggregation”

If, in the same month, family members enrolled in the same insurance plan (for employees’ health insurance, the insured person and their dependents) each receive treatment at medical institutions, or if one person is treated at more than one medical institution, their out-of-pocket payments can be combined and compared against the ceiling amount. This is called “household aggregation” (世帯合算). For people under 70, only amounts of ¥21,000 or more paid at a single medical institution (counted separately for inpatient/outpatient and medical/dental) are eligible to be combined (Health Insurance Act Enforcement Order, Article 41, Paragraph 1). For people 70 and over, all amounts can be combined.

Keeping Counter Payments at the Ceiling: My Number Health Insurance Card or Certificate of Eligibility for Limit Application

One way to receive the high-cost medical expense benefit is to pay the 30% co-payment at the counter and then apply afterward to get the excess refunded. Separately from this, there is a way to keep the counter payment at the ceiling amount from the start. The Ministry of Health, Labour and Welfare (MHLW) advises that, to receive this treatment, you need either to use a My Number Health Insurance Card (マイナ保険証, a My Number Card registered for use as a health insurance card) or to obtain a “Certificate of Eligibility for Limit Application” (限度額適用認定証, gendogaku tekiyō nintei-shō) in advance.

• My Number Health Insurance Card: According to Kyōkai Kenpo’s guidance, at a medical institution or pharmacy that has introduced online eligibility verification (オンライン資格確認), the limit information is passed to the institution automatically, so no application for a certificate is needed. However, in Kyōkai Kenpo’s table for people 70 and over, those in the bracket exempt from resident tax are still required to apply for the certificate even when using a My Number Health Insurance Card.
• Certificate of Eligibility for Limit Application: If you are treated at a medical institution that has not introduced online eligibility verification, or if your My Number has not been registered with your insurer, you apply for the certificate and present it at the counter. It is not issued retroactively for months before the month you apply.

Because the income brackets are scheduled to be revised in August 2027, Kyōkai Kenpo sets the validity of Certificates of Eligibility for Limit Application issued from August 2026 at no later than July 31, 2027, and asks anyone who still needs one to apply again from August 2027 onward. How to show proof of insurance is covered in our article on preparing before a hospital visit in Japan, and which insurance to enroll in is covered in our article on enrolling in health insurance and pension.

Where to Apply, and the Two-Year Deadline

Where to apply is determined by the insurance you are enrolled in. The MHLW advises checking the name of your insurer through Mynaportal (マイナポータル) or your “certificate of eligibility” (資格確認書), and then making inquiries as follows.

• If it says “〇〇健康保険組合” (a health insurance society), “全国健康保険協会” (Kyōkai Kenpo), or “〇〇共済組合” (a mutual aid association): contact that insurer (for Kyōkai Kenpo, the prefectural branch)
• If it says “〇〇国民健康保険組合” (a National Health Insurance society): contact that National Health Insurance society
• If it shows the name of a municipality: contact that municipality’s National Health Insurance counter

The right to receive the high-cost medical expense benefit is extinguished by the statute of limitations two years after the date it could first be exercised (Health Insurance Act, Article 193; National Health Insurance Act, Article 110). Check with your insurer for exactly when that period starts. Kyōkai Kenpo also has a “High-Cost Medical Expense Loan Program” (高額医療費貸付制度) that advances, interest-free, 80% of the expected benefit amount.

From the 2025 Postponement to the August 2026 Revision

The ceiling increase was postponed once before. According to MHLW materials, the government had planned to raise the ceiling amounts by 2.7% to 15% by income bracket starting in August 2025, and to subdivide the brackets further from August 2026 onward. However, on March 7, 2025, then-Prime Minister Shigeru Ishiba, after meeting with patient groups, announced that implementation of the entire revision — including the increase planned for August 2025 — would be put on hold, and that the policy would be reconsidered by autumn.

The MHLW explains that, with this revision, while it asks mainly people with shorter treatment periods to bear an additional burden, it kept the repeat-month reduction amount unchanged and introduced the annual cap out of consideration for the burden on people who continue treatment over a long period.

The New “Annual Cap”

The annual cap sets a ceiling on the total out-of-pocket payments over the 12 months from August 1 each year to July 31 of the following year (Health Insurance Act Enforcement Order, Article 41-2, and Article 42, Paragraph 11). This is the amount in the “Annual cap” column of the table above; once the total exceeds the annual cap, the excess is refunded by the insurer. The MHLW explains that even for someone whose payments never reach the monthly ceiling on their own, once the annual cap is reached no further burden is required for the rest of that year.

Because the first calculation period runs from August 2026 to July 2027, refunds under the annual cap will not begin until after that. Kyōkai Kenpo states that it will start accepting applications for the annual cap from August 2027, and that refunds applying the ¥410,000 annual cap to people confirmed to have a standard monthly remuneration of ¥150,000 or less will likewise begin from August 2027 onward.

From August 2027, the Brackets Become More Finely Divided

According to MHLW materials, from August 2027 each of the four brackets other than the one exempt from resident tax will be split into three, bringing the total for people under 70 to 13 brackets. For example, the current bracket ウ (standard monthly remuneration of ¥280,000 to ¥500,000) will be divided into ¥280,000–¥340,000, ¥360,000–¥410,000, and ¥440,000–¥500,000, with monthly ceilings of ¥85,800, ¥98,100, and ¥110,400 respectively (each plus 1% of the cost of treatment). The repeat-month reduction amounts are to remain unchanged even after this subdivision.

Guidance Available in Ukrainian

The Ukrainian-language edition of the Guidebook on Living and Working (7th edition, March 2025) explains the high-cost medical expense benefit under the heading “Великі витрати на медичне обслуговування.” However, this edition was produced before the August 2026 revision, so it does not cover new features such as the annual cap. As of September 2026, the MHLW’s and Kyōkai Kenpo’s guidance on the revision is available only in Japanese. If you are not sure where to ask, see our article on counters where you can consult in Ukrainian. For children’s medical expenses, subsidies from the municipality you live in can reduce out-of-pocket payments further (see our article on child medical expense subsidies). Injuries or illnesses caused by work or the commute to work are covered not by health insurance but by workers’ accident compensation insurance.