"For my retirement, which is better — iDeCo or NISA?" Both are advantageous systems that make your investment gains tax-free, but their characters are completely different. To state the conclusion first, for many people the right answer is not "one or the other" but using both together with separate roles. This article organizes the two differences in a table and explains how to set priorities according to your income and goals.
The difference between iDeCo and NISA (quick-reference table)
| iDeCo | NISA | |
|---|---|---|
| Main purpose | Retirement funds (private pension) | Any purpose you like |
| Tax benefit | Contributions are fully income-deductible + tax-free gains + a deduction also applies at withdrawal | Gains and dividends are tax-free (no deduction for contributions) |
| Withdrawal | In principle not possible until age 60 | Can be withdrawn anytime |
| Limit | ¥12,000–¥68,000 per month (varies by occupation) | ¥3.6 million per year, ¥18 million lifetime |
| Account management fee | Yes (monthly) | None (product costs only) |
| Eligible products | Time deposits, insurance, investment trusts | Investment trusts, listed stocks, etc. |
There are two biggest differences. With iDeCo, in exchange for "your current income tax and residence tax going down (income deduction)" you get "no withdrawals until age 60." With NISA, in exchange for "being able to withdraw anytime" there is "no income deduction for contributions."
iDeCo's strength = "income deduction for contributions"
iDeCo contributions are fully income-deductible, lightening your income tax and residence tax for that year. For example, if a person whose taxable income falls in the 20% income tax + 10% residence tax bracket contributes ¥240,000 a year, the calculation is that taxes fall by about ¥72,000 a year (NISA does not have this effect)[National Tax Agency No.1135]. At the time you receive it, you can also use the retirement income deduction and the public pension deduction. For details, see iDeCo's tax-saving effect and filing steps.
| Occupation, etc. | iDeCo contribution limit (monthly, current) |
|---|---|
| Self-employed (Category 1) | ¥68,000 (combined with the National Pension Fund, etc.) |
| Employee (no corporate pension) | ¥23,000 |
| Employee (with corporate DC / DB) | ¥20,000 (within the combined limit) |
| Public servant | ¥20,000 |
| Full-time homemaker (Category 3) | ¥23,000 |
Under the system revision, the contribution limit is planned to rise from ¥68,000 to ¥75,000 for the self-employed, and for employees and public servants to ¥62,000 per month combined with corporate pensions (abolishing the standalone iDeCo limit), and the age at which you can enroll is set to expand from under 65 to under 70. Please confirm the latest enforcement details officially[iDeCo official].
NISA's strength = "the freedom to withdraw anytime"
NISA has no income deduction for contributions, but you can sell and withdraw anytime you need to, the allowance is large at ¥3.6 million per year and ¥18 million lifetime, and there is no account management fee[Financial Services Agency]. Its appeal is that you can use it without limiting the purpose — education costs, housing, retirement, and so on (for how it works, see the New NISA usage guide).
Which to prioritize? (how to think about it by type)
- You pay income tax and residence tax and want to reliably save retirement funds → the income-deduction benefit of iDeCo is large. Start with iDeCo.
- You value money you'll use in the near future / liquidity → prioritize NISA, which you can withdraw freely.
- You have low income, or are a full-time homemaker, so the income-deduction effect is small → since the income-deduction benefit is thin, centering on NISA is reasonable.
- You are self-employed and want to save a lot on tax → iDeCo's limit is high and the income deduction is effective. Use it together with NISA.
① First secure emergency living funds (a few months of living expenses) in cash → ② If you pay income tax, go after the income deduction with iDeCo → ③ Then invest any further surplus flexibly in NISA. This is a manageable order for most people.
FAQ
Can I use iDeCo and NISA together?
Yes. Both make investment gains tax-free, and because their purposes and characters differ, the basic approach is to use them together with separate roles.
In the end, which should I prioritize?
If you pay income tax and residence tax and want to reliably save retirement funds, iDeCo (the income deduction is effective). If you value liquidity, NISA. For people with low income, centering on NISA is reasonable.
Why can't iDeCo be withdrawn until age 60?
Because it is a private pension system for retirement funds. In exchange, contributions are fully income-deductible and there are tax preferences at the time of receipt too. Money you plan to use soon is better suited to NISA.
Will the iDeCo contribution limit change?
Under the December 2026 revision (from contributions made in January 2027 onward), it is planned to rise from ¥68,000 to ¥75,000 for the self-employed, to ¥62,000 per month for employees and public servants combined with corporate pensions, and the enrollment age is set to expand to under 70.
Summary
Reference links (sources)
This article is based on the following materials from public bodies and official sources (neutral, primary information). Because contribution limits and systems are revised, please confirm the latest content before use.
- iDeCo official site (National Pension Fund Association) (in Japanese)
- National Tax Agency No.1135 Deduction for small enterprise mutual aid premiums, etc. (iDeCo) (in Japanese)
- Financial Services Agency NISA special website (in Japanese)
* This article is general information, not an investment solicitation or tax advice. Investment decisions are your own responsibility; please confirm the latest system officially.