Japan's Annual Tax Schedule Guide: When to Handle Furusato Nozei, Medical Expense Deductions, and Side Income Tax Filing
Why Thinking in Terms of a Yearly Schedule Matters
Furusato nozei (Hometown Tax Donation Program), medical expense deductions, and side income tax filing each have their own rules — but if you don't know when to act on each one, it's easy to miss a deadline.
The key difference comes down to timing:
- Furusato nozei: donations must be completed by December 31 of the same year (a strict within-year rule)
- Tax return filing (kakutei shinkoku): generally done between February 16 and March 15 of the following year
- Medical expense deductions: usually filed together with your tax return, but if you forget, you can still file a refund claim retroactively for up to five years
In other words, furusato nozei is the only one of these that can't be undone once the year ends. Medical expense deductions give you a much longer window to catch up. Understanding this distinction makes the whole year feel far less overwhelming.
January–March: Tax Return Season for the Previous Year
If you have side income, January through March is the most important stretch of the year. You'll report your income from the previous calendar year (January 1 to December 31) to the tax office, typically between February 16 and March 15.
For details on how much side income requires filing and what documents you'll need, see our guide on side income tax filing.
Side income tax filing checklist
Medical expense deductions are also typically filed alongside your tax return during this period, so it's worth gathering a year's worth of medical receipts ahead of time.
April–September: Your Window for Retroactive Refund Claims on Medical Expenses and Furusato Nozei
Missed the filing season, or forgot to claim a medical expense deduction? You're not necessarily out of luck.
Medical expense deductions and missed furusato nozei claims (cases where a tax refund is generated) can be submitted as a retroactive refund claim (還付申告) for up to five years, starting from January 1 of the year following the relevant tax year. So if you forget to claim your 2026 medical expense deduction, you'd have until December 31, 2031 (starting January 1, 2027) to file it.
For details on what qualifies as a medical expense and how the deduction is calculated, see our guide here.
How medical expense deductions are calculated
April through September is also a relatively quiet stretch after tax season ends — a good time to organize old receipts or run the numbers on your furusato nozei budget for the year.
Note: If you had taxable side income and didn't file a return, that's a different situation — it becomes a "late filing" (期限後申告) rather than a refund claim, and can trigger penalties (無申告加算税, 延滞税) regardless of the five-year window. If that applies to you, it's worth addressing sooner rather than later.
October–December: Furusato Nozei Must Be Done Within the Year
Of the three, furusato nozei is the one rule with no do-overs. Donations must be made between January 1 and December 31 of the same year to count toward that year's tax deduction. Once the new year starts, that window is gone for good.
December tends to get crowded, and popular municipalities or return gifts can sell out before the deadline. If you haven't calculated your donation limit yet, it's worth doing sooner rather than later.
For a detailed look at how the deduction limit is calculated, see our furusato nozei guide.
How furusato nozei deduction limits work
You can also run a quick simulation using the zeicalc tax calculator — just enter your income and household details to get an estimate of your limit.
A Final Note
Furusato nozei, medical expense deductions, side income filing — understanding each one individually isn't enough if you don't know when to act.
I've personally missed the furusato nozei deadline myself. Year-end work always gets busy, and I assumed "there's still time this year" — only to realize, too late, that December 31 had already passed. Since then, I've made furusato nozei a fixed item on my October to-do list every year.
I hope this guide serves as a yearly map so you don't have to repeat that mistake.
Summary: Your Annual Tax Schedule at a Glance
| Period | What to Do | Things to Watch For |
|---|---|---|
| Jan–Mar | File your tax return (side income, medical expense deductions) | Reports the previous year's income; deadline is around March 15 |
| Apr–Sep | File retroactive refund claims for medical expenses or missed furusato nozei claims | Can go back up to five years from January 1 of the following year |
| Oct–Dec | Make your furusato nozei donations | Must be completed by December 31 — donations after the new year don't count for that year |
For more detail on each topic, check out the linked guides above. And for calculating your furusato nozei deduction limit or other tax estimates, the tools at zeicalc can help.