This is exactly the kind of thing that quietly leaves money on the table because it's only explained in Japanese. Mio reads the National Tax Agency (NTA) rules and lays out the math in English. This is general information, not tax advice — verify your case with the NTA.
The medical expense deduction (iryōhi kōjo) works on a threshold. You add up the medical costs your household actually paid during the calendar year, subtract any reimbursements (insurance payouts, the High-Cost Medical Expense benefit, birth lump-sums, etc.), and then subtract a floor. That floor is ¥100,000 — or 5% of your total income if that is lower (which applies when your yearly income is under roughly ¥2 million). Whatever is left over is your deduction, up to a cap of ¥2 million.
The deduction is for treatment, not comfort or beauty. A rough guide (not exhaustive — check the NTA):
| Usually counts ✅ | Usually does NOT count ❌ |
|---|---|
| Doctor, dentist, hospital treatment fees | Cosmetic / aesthetic procedures |
| Prescription medicines | Vitamins & general health supplements |
| Childbirth & certain pregnancy costs | Routine health checks with no illness found* |
| Necessary transport to hospital (e.g. train, bus, sometimes taxi) | Your own car's fuel & parking |
| Some dental treatment & necessary devices | Purely convenience or private-room upgrade fees |
*If a health check leads to a diagnosis and treatment, the treatment can qualify. Rules on transport and edge cases are specific — see the NTA source below.
Two things happen. First, the deduction lowers your taxable income, so your income tax refund is roughly your income-tax rate × the deductible amount. Second, the same deduction usually lowers next year's resident tax (a flat ~10% effect). So the combined benefit is bigger than the income-tax refund alone.
| Medical paid (after reimbursements) | Deductible (− ¥100k) | Rough refund* |
|---|---|---|
| ¥150,000 | ¥50,000 | ~¥10,000 (5% income tax + 10% resident tax) |
| ¥300,000 | ¥200,000 | ~¥40,000 (10% + 10%) |
| ¥600,000 | ¥500,000 | ~¥150,000 (20% + 10%) |
Illustrative only. Your income-tax rate depends on your income bracket; the resident-tax effect is approximate and appears the following year. Real figures depend on your full return — verify with the NTA.
If you didn't hit ¥100,000 in overall medical bills but you buy a lot of eligible over-the-counter medicines (marked as switch-OTC products), there's a separate Self-Medication deduction. It kicks in above a much lower floor of ¥12,000 in qualifying purchases, deducting the excess up to ¥88,000. It requires that you did something for your own health that year (a check-up, vaccination, etc.).
Important: you can claim the regular medical expense deduction OR Self-Medication — not both in the same year. Pick whichever gives the larger deduction.
This deduction is never applied automatically by your employer's year-end adjustment (nenmatsu chōsei). You claim it yourself by filing a tax return (kakutei shinkoku), typically for the previous calendar year during the filing season (mid-Feb to mid-Mar). You submit a medical expense statement summarizing the costs; you generally don't attach every receipt, but you must keep receipts for five years in case the tax office asks. If you missed a past year, refund claims can usually be filed for up to five years back.
Yes. This deduction is about your tax residency and Japanese-source income, not your nationality. If you live in Japan, pay Japanese income tax, and paid the medical bills for yourself or a family member you support, you can claim it the same way a Japanese taxpayer does. A visa status alone doesn't disqualify you.
Add up your household's medical receipts for the year. Past ~¥100,000 (after reimbursements), file a tax return and claim iryōhi kōjo. Under that but heavy on eligible OTC meds? Check Self-Medication instead. Either way, the refund only exists if you file — the meter doesn't run itself.
Mio