High-Cost Medical Care Benefit Calculator

Japan's public health insurance caps how much you pay out-of-pocket in a single month, no matter how large the bill. The Kogaku Ryoyohi benefit refunds anything above your income-based cap. Enter your bill to see your cap and refund.

Inputs

Total medical bill for the month (100%)

×10,000 JPY

The full (pre-insurance) amount, i.e. before your 30% share. 1,000,000 JPY

Income bracket (annual)

4th+ time within 12 months (multiple-month reduction)

Result

Refund (high-cost medical benefit)

212,570JPY

30% counter payment (before refund): 300,000 JPY
Your monthly self-pay cap: 87,430 JPY
Final out-of-pocket (after refund): 87,430 JPY

Estimate for under-70 insured persons (FY2026 brackets). The High-Cost Medical Care Benefit (Kogaku Ryoyohi) caps your monthly self-pay; the excess over the cap is refunded (or pre-empted with a Limit Certificate). Hospital meal/room-difference fees and items outside insurance are not counted.

How it works

You normally pay 30% at the counter. If that 30% exceeds your monthly cap, the excess is refunded.
For an average-income earner (bracket “~3.7M–7.7M”), the cap is roughly 80,100 JPY + 1% of the bill above 267,000 JPY.
Get a Limit Certificate (gendogaku tekiyo nintei-sho) in advance so the hospital only charges up to the cap — no need to front the full amount.
From the 4th qualifying month within 12 months, a lower “multiple-month” cap applies.
Not counted: hospital meals, private-room (差額ベッド) fees, and treatments outside insurance.

FAQ

Q. Do foreigners qualify?: Yes. Anyone enrolled in Japanese public health insurance (Shakai Hoken or National Health Insurance) is covered, regardless of nationality. Apply through your insurer (employer’s society / kenpo, or your city’s NHI desk).
Q. How do I get the refund?: If you paid the full 30%, file a high-cost claim with your insurer; the refund arrives a few months later. To avoid fronting the cash, request a Limit Certificate before a planned hospitalisation and show it at the counter.

Estimate for insured persons under 70 (FY2026 brackets). Ages 70+ have different caps. See the Japanese version and the health-insurance guide for more.