Tax on side income in Japan, in plain English

First, a note

This is general information, not tax advice. Only a licensed tax accountant (税理士, zeirishi) can advise on your own situation. The tax office's free consultations and the National Tax Agency's website are good places to check.

Income is what's left after expenses

Japanese tax counts income (所得, shotoku), not what you were paid. For side work, income is what clients paid you minus your expenses: transport to jobs, a share of your phone bill, the platform's fee, and so on. Keep receipts and a simple list from day one.

If you have a salaried job

Your employer handles tax on your salary through the year-end adjustment (年末調整). For your side income:

The trap: the ¥200,000 rule is only about the national income tax return. Resident tax has no such exemption. Many people skip the city declaration because of the rule, and get a letter later. And if you file a return anyway (say, to claim medical expenses or a hometown tax donation), you must include the side income on it, however small.

Worried your employer will notice the side income through your resident tax? When you file, you can choose to pay the resident tax on side income yourself (普通徴収) rather than through your salary. Check the box for it on the form. This works for freelance income like Pro Gaijin earnings, not for a second part-time job's salary.

If side work is your main income

• You generally file a return if your total income is above the basic deduction (基礎控除), which was raised in the 2025 tax reform. Check the current amount on the National Tax Agency site.
• If you do this as a business, you can file a business start notice (開業届, kaigyō todoke) at the tax office, and choose blue-form filing (青色申告, aoiro shinkoku) for a larger deduction in return for proper bookkeeping.
• You'll pay National Health Insurance and National Pension yourself, based on your income.

When and how to file

• Filing period: usually mid-February to mid-March, for the previous calendar year (January to December).
• How: online with e-Tax (easiest with a My Number card and a smartphone), at the tax office, or by post.
• Help: tax offices run free consultation corners in filing season, and there are English guides on the NTA site.
• Leaving Japan mid-year? Different rules apply. Leaving Japan: the checklist.

Do I need to charge consumption tax or register for invoices?

Small sellers with taxable sales of ¥10 million or less are usually exempt from consumption tax (the sales counted are from two years earlier), and most people helping individuals don't need to register for the invoice system (インボイス制度). Your clients are private people who don't need invoices to claim tax back.

Keep it simple: a monthly habit

1. 1Once a month, note what you were paid (your platform earnings page or bank statements show it).
2. 2Snap photos of receipts for anything you spent on the work.
3. 3Keep both in one folder per year. Filing then takes an evening, not a week.