iDeCo tax deduction
Contribution deductions, tax-deferred growth, withdrawal taxation, eligibility, and caps.
iDeCo contributions are fully deductible from income as small-business-mutual-aid-type premiums, growth inside the account is tax-deferred, and withdrawals get pension- or retirement-income treatment — with contribution caps that depend on your employment and pension status.
Effective: 2026-01-01 to 2026-12-31
Professional review pending — treat as draft and confirm with the authorities.
Key points
- Contributions are fully deductible from taxable income.
- Investment growth is tax-deferred inside the account.
- Withdrawals are taxed as pension or retirement income.
- Caps depend on your employment and pension category; funds lock until ~60.
The three tax benefits
iDeCo has three tax advantages: contributions reduce your taxable income now (claimed via the small-business-mutual-aid-type premium deduction), investment gains are not taxed while inside the account, and at payout you get pension-income or retirement-income treatment depending on how you take it. Contribution caps depend on whether you are an employee, civil servant, self-employed, or a dependent spouse.
Payout planning
A lump-sum iDeCo payout uses the retirement-income deduction, which can overlap with a company retirement allowance and its service years — so taking both in a way that double-counts the deduction may be disallowed, and timing matters. Because funds lock until around age 60 and payout rules are intricate, model the payout before you rely on it.
Who this is for
- Long-term retirement savers
- Freelancers wanting a deduction
What this is not
- Money you may need before ~60
- iDeCo and a retirement allowance can interact on the retirement-income deduction — model the payout timing.
Frequently asked questions
Do I need to file a tax return in Japan?
Many employees do not, because tax is settled by year-end adjustment (年末調整). You generally must file (確定申告) if you have side income over ¥200,000, two or more employers, self-employment income, sizeable investment or crypto gains, or you want to claim deductions like large medical costs or a first-year mortgage credit. Filing season is Feb 16 – Mar 15 via e-Tax. When unsure, check the NTA guidance or ask a 税理士.