- Your limit is set by side-business income (profit), not sales. The special portion of the resident-tax credit is capped at 20% of your income-based resident tax, so more profit means a higher limit
- If your side business counts as miscellaneous income, a loss cannot offset your salary. Your limit will not fall, but a loss will not raise it either
- File a tax return for your side income and the one-stop exception no longer applies. Every donation, including those you already applied for, goes on the return
- Even if side income of ¥200,000 or less spares you an income tax return, you still need a separate resident tax declaration. Since October 2025, soliciting donations through sites that award points has been banned
Key points: frequently asked questions
- Q: Does a side business change my furusato nozei limit?
- A: More side-business income (profit) pushes the limit up. According to MIC, the special portion of the resident-tax credit is capped at 20% of your income-based resident tax, and that tax is calculated on all your income, side business included.
- Q: Can I use the one-stop exception if I file a tax return for my side income?
- A: No. Once you file a tax return, the one-stop exception does not apply, and you must list every donation made that year under the donation deduction on your return.
This article is for salaried employees who also run an affiliate or other side business in Japan. It is general, educational information that organises what the Ministry of Internal Affairs and Communications (MIC) and the National Tax Agency (NTA) have published about furusato nozei and side income, not tax advice. For your own deduction limit, income category and whether you need to file, check with your local tax office, your municipality or a licensed tax accountant (zeirishi).
Your limit is set by profit, not sales
Furusato nozei (hometown tax donation) lets you donate to a Japanese municipality and have everything above ¥2,000 credited against your income tax and resident tax, up to a limit. Many people type their salary into an online simulator and trust whatever number comes out. That is where new side earners slip first. Most simulators for employees are built around the figures on your salary withholding slip. Whatever you earn on the side is not in the calculation unless you add it yourself.
MIC's page on how the deduction works explains that it has three parts: the income tax deduction, the basic portion of resident tax, and the special portion of resident tax. Everything except your ¥2,000 out-of-pocket amount is credited as long as the special portion stays within 20% of your income-based resident tax (shotoku-wari). That 20% is the ceiling.
The deduction has three parts: ① income tax (an income deduction) ② resident tax, basic portion ③ resident tax, special portion.
As long as ③ stays within 20% of your income-based resident tax, everything above ¥2,000 is credited in full.
Income-based resident tax is calculated on all your income, not just your salary. So profit from a side business raises it, and your limit rises with it. Simple enough so far.
The catch is that what counts is income, not sales. Earn ¥600,000 a year in affiliate commissions, and your resident tax still depends on what is left after expenses. If you apportion home costs as business expenses, estimating from sales will overstate your limit (we cover apportionment in our home-office apportionment article).
The side-income trap: a miscellaneous-income loss cannot offset your salary
Does a loss-making year lower your limit? It depends on your income category.
NTA Tax Answer No.2250 (offsetting gains and losses, son'eki tsusan) says only losses from real estate, business, timber and capital gains (joto) income can be offset against other income. No.1500 (miscellaneous income) says a loss arising in miscellaneous income cannot be offset against other income.
| Income category of your side business | How a loss is treated | Effect on your furusato nozei limit |
|---|---|---|
| Miscellaneous income (zatsu shotoku) | Cannot be offset against salary or other income | Salary income stays the same, so the limit does not fall (but it does not rise either) |
| Business income (jigyo shotoku) | Can be offset | The loss is deducted from salary income, lowering your resident tax and possibly your limit |
Employees' side income is often reported as miscellaneous income, and in that case a side-business loss will not shrink your limit. If you report business income, though, using last year's limit in a loss year can push your donations over the cap and raise what you pay out of pocket.
Whether your side income is business or miscellaneous income depends on the facts of your activity, and this article cannot decide that for you. If you are unsure, ask your tax office or a zeirishi. For the bigger picture on side-income tax, see affiliate tax basics.
File a tax return and the one-stop exception disappears
The one-stop exception (one-stop tokurei) lets you claim the donation deduction without filing a tax return. According to MIC, it is only for salaried workers and others who would not otherwise need to file, and only if you gave to five or fewer municipalities in the year.
Here is where side earners get caught. MIC states that the exception does not apply to anyone who files a tax return, or who applied for it with six or more municipalities. The moment your side income passes ¥200,000 and you have to file, the one-stop applications you already sent stop counting.
"I already sent the one-stop forms, so my return only needs the side income." That is the trap. If you file, you must list every donation made that year in the donation deduction section, including those covered by one-stop applications. A donation you leave off is not deducted. It is just a donation.
Keep the donation receipts that municipalities send you, including those for one-stop donations. You will need every amount when you file. Our tax return guide walks through filing for side income.
"Under ¥200,000, do nothing" is an income tax rule only
A salaried worker whose non-salary income is ¥200,000 or less a year may not need to file an income tax return. That rule, however, applies only to the income tax return. Resident tax has no equivalent, so your side income needs a separate resident tax declaration to the municipality where you live (see our resident tax basics).
Another case that is easy to miss: filing a return because of furusato nozei. Say you gave to six or more municipalities, cannot use one-stop, and decide to claim the deduction through a tax return. In principle, that return should include your side income too, even if it is ¥200,000 or less. The "no filing needed under ¥200,000" treatment is for people who do not file a return in the first place.
| Your situation | How to claim the donation deduction | Reporting your side income |
|---|---|---|
| Side income over ¥200,000 | List all donations on your tax return (one-stop is void) | Include it in your tax return |
| Side income ¥200,000 or less, five or fewer municipalities | List all donations on your resident tax declaration (filing it voids one-stop) | A separate resident tax declaration is needed |
| Side income ¥200,000 or less, six or more municipalities | List all donations on your tax return | Include it in your tax return |
The point people overlook: as many municipalities explain, the one-stop exception becomes void not only when you file a tax return but also when you submit a resident tax declaration. If your side income is ¥200,000 or less and you file a resident tax declaration, list your donations on it too, and you will not lose the deduction. If you forget, you will need to file again with the donations included.
Since October 2025, point rewards are banned
MIC revised the criteria for designating which municipalities can receive furusato nozei. From October 1, 2025, soliciting donations through portal sites and similar channels that award points or the like for donating is banned. If you used to pick a site by how many percent in points it paid back, that basis is gone.
For a side earner, there is now less reason to donate right up to your limit to chase point rewards. In a year when you are unsure of your estimate, leaving some headroom is the more rational choice.
Two deadlines: donate by December 31, send one-stop forms by January 10
Only donations made between January 1 and December 31 count for that year. For last-minute year-end donations, the date recorded can shift depending on how you pay, so check the guidance from the municipality or site.
One-stop application forms must reach the municipality by January 10 of the following year. The same deadline applies to change notices, for example after a change of address. If your side profit will not be clear until the new year, plan to claim through a tax return rather than relying on one-stop, and you will not be caught short.
Four steps to avoid a year-end scramble
There is not much to do, but the order matters.
Your payslip alone does not set your furusato nozei limit. For side earners, your estimate of side profit is your estimate of the limit. Working out that profit before rushing to donate, rather than racing the year-end figures, protects you from both missed deductions and overpaying.
Frequently asked questions
[Disclaimer] OlympTrade is an offshore platform that is not registered with Japan's Financial Services Agency (FSA), so Japan's investor protection schemes do not apply. This article is general, educational content from the Kingfin editorial team and is not tax advice. It summarises information published by MIC and the NTA and does not determine any individual taxpayer's deduction limit or whether they need to file. Laws and circulars may be amended. Based on information as of publication (October 6, 2026).
