The Threshold for Part-Time Workers to Avoid Losing Out on Taxes, Insurance, and Deductions

Income tax threshold

Income tax becomes payable when annual income exceeds 1.03 million yen.

1.03-million-yen threshold = Employment income deduction of 550,000 yen + Basic deduction of 480,000 yen (from Reiwa 2 onward)

Resident tax threshold

Resident tax becomes payable when annual income exceeds 1 million yen. Depending on the municipality, the threshold may be 980,000 yen instead of 1 million yen. (※1)

1-million-yen threshold = Employment income deduction of 650,000 yen + Resident tax exemption deduction of 350,000 yen

Social insurance threshold

You must enroll in social insurance if any of the following applies.

(1) Your weekly working hours or monthly working days are at least three-quarters of those of a regularly employed worker.

(2) Even if your weekly working hours or monthly working days are less than three-quarters of those of a regularly employed worker, all of the following apply. (※2)

• You work at least 20 hours per week.


• You are expected to be employed for at least 2 months.


• The employer has at least 101 employees (at least 51 from October 2024 onward).


• You are not a student.


• Your monthly wages are at least 88,000 yen (annual income of approximately 1.06 million yen or more).

(3) Your annual income exceeds 1.3 million yen.

(Note) For social insurance purposes, annual income includes transportation allowances.

Special spousal deduction threshold

Spouse's annual income exceeds 1.5 million yen: The husband's deduction decreases gradually.

Spouse's annual income is 2,016,000 yen or more: The husband's deduction is 0 yen.

If the working student deduction applies, the tax-exempt income limit rises from 1.03 million yen to 1.3 million yen, but you cease to qualify for your parent's dependent deduction.


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