Introduction
In Japan, in recent years, diverse working styles such as side jobs, freelancing, and online businesses have been spreading. For foreign individuals, there has been an increase in cases of earning side income during their stay in Japan or conducting online business for overseas clients.
However, under Japanese income tax law, side income is not uniformly treated the same. In practice, whether that income falls under "miscellaneous income" or "business income" significantly affects loss offsetting, blue return filing, necessary expenses, and tax audit risks.
Especially for foreign individuals, additional international tax issues may arise, such as the distinction between residents and non-residents in Japan, the relationship with foreign-source income, and the relationship with overseas remittances.
This article organizes the classification criteria for side income in Japan, the practical judgment points, and the risks in tax audits.
1. The difference between "miscellaneous income" and "business income" in Japanese income tax
Under Japanese income tax law, individual income is classified by income category. The issues related to side jobs and freelance income mainly fall into the following two categories.
・Business income
・Miscellaneous income
Business income refers to income derived from business activities that are conducted continuously and repetitively at one's own risk and calculation.
On the other hand, miscellaneous income refers to income that does not fall under other income categories, often arising from side, temporary, or small-scale activities.
For example, the following cases are likely to be problematic.
・Consulting work done by a company employee on their day off
・Remote development work done by a foreign engineer for overseas companies
・SNS advertising income
・YouTube revenue
・Translation・Design・Writing services
・Cryptocurrency-related income
・Online instructor income
In practice, it is important to note that it is not a simple judgment of "side job means miscellaneous income" or "filed a business registration means business income."
2. Criteria for determining if it qualifies as business income
The National Tax Agency considers the following circumstances comprehensively regarding the qualification of business income.
・Is there a profit motive or compensation?
・Is there continuity or repetition?
・Is it operated independently as a social status?
・Does it have human and material resources?
・Is there a considerable scale of income?
・Is there a reality of it being a main business?
For example, if it is a one-off side job or only a temporary income of a few tens of thousands of yen, it is likely to be judged as miscellaneous income.
On the other hand, if one continuously acquires customers, provides services independently, and has a certain scale of sales, it is more likely to qualify as business income.
Since 2022, the National Tax Agency has indicated a cautious approach to determining business income in cases such as "generally being in the red for about three years." However, being in the red does not immediately mean it becomes miscellaneous income; it is a comprehensive judgment of the business reality.
3. Different tax implications for miscellaneous income and business income
The difference in income classification is not just a matter of naming. There are significant differences in tax treatment as follows.
First, if it qualifies as business income, the blue return system can be applied.
By meeting certain requirements,
・Blue return special deduction
・Carryover deduction for losses
・Salaries for dedicated employees
・Special provisions for small depreciable assets under 300,000 yen
and many other tax benefits become available.
On the other hand, in the case of miscellaneous income, blue return benefits cannot be utilized, and losses are generally not allowed to be offset against other income.
Additionally, the scope of necessary expenses is often strictly verified by the tax office in cases of miscellaneous income.
Especially in recent years, due to the side job boom, there have been increasing cases where tax audits raise issues such as "Is it not essentially a hobby activity?" or "Are private expenses mixed in?"
4. Issues unique to foreign individuals
For foreign individuals, in addition to the same income classification determination as Japanese individuals, additional issues arise in international taxation.
Typical examples include the following.
・Are they a resident or non-resident of Japan?
・Does it qualify as foreign-source income?
・Taxation relationship of compensation from overseas clients
・Applicability of tax treaties
・Relationship with overseas remittances
For example, foreign individuals who qualify as residents of Japan are generally subject to worldwide income taxation.
Therefore, online business compensation received from overseas companies may also be subject to taxation in Japan.
On the other hand, for non-permanent residents, there may be cases where the taxation rules for foreign-source income and remittance of foreign-paid income become problematic.
Also, there are many cases where it is misunderstood that "overseas clients are not subject to Japanese taxation," but in reality, if services are provided within Japan, there is a high possibility of being subject to Japanese taxation.
Furthermore, there are cases where adjustments with foreign tax credits and tax treaties are necessary, and careful consideration is required when cross-border transactions are involved.
5. Points that are likely to be problematic in tax audits
Regarding side jobs, in recent years, information gathering by tax authorities has been strengthened.
In particular, the following items are likely to be key verification points in tax audits.
・Sales recording omissions
・Undeclared overseas accounts
・Undeclared platform income
・Private use of expenses
・Arbitrary determination of miscellaneous income and business income
・Undeclared income related to cryptocurrency assets
For example, overseas deposits through PayPal, Stripe, Wise, and overseas bank accounts may also be subject to verification in tax audits.
Additionally, regarding income from social media and video streaming platforms, there is a possibility of reconciliation with platform data and remittance history.
Furthermore, if activities that are originally considered miscellaneous income are formally declared as business income for the purpose of benefiting from blue return filing, there is a risk of tax denial.
6. Practical response points
When foreign individuals engage in side jobs or freelance activities in Japan, the following practical responses are important.
First, it is important to conduct a reasonable organization of income categories in advance.
In addition,
・Contract document preservation
・Invoice management
・Expense receipt preservation
・Separation of business accounts
・Bookkeeping
・Management of overseas remittance records
and so on, it is necessary to establish a receipt management system that is conscious of tax audits.
Moreover, if there are transactions with overseas clients, comprehensive consideration is required, including not only income tax but also consumption tax, tax treaties, and foreign tax credits.
In particular, depending on the relationship with the duration of stay in Japan and residency status, unexpected tax relationships may arise, so early consultation with a specialist is desirable.
7. Conclusion
Regarding side job income in Japan, the tax treatment differs significantly depending on whether it is classified as "miscellaneous income" or "business income."
However, in practice, comprehensive judgments based on actual activities are made rather than formalities, so simple classifications such as "because I submitted a business registration, it is business income" or "because it is a side job, it is miscellaneous income" are not appropriate.
In particular, for foreign individuals, the addition of international tax issues can complicate tax risks.
When engaging in side jobs or freelance activities, it is important to conduct comprehensive considerations that include not only domestic taxation in Japan but also cross-border taxation, and to carry out appropriate filing and receipt management.
If you require our support, please contact us Here.