New NISA Simulator (Tsumitate & Growth Investment Quotas)
Enter your monthly Tsumitate (installment) investment and annual Growth investment amounts along with an expected return, and simulate the future tax-free balance under Japan's New NISA lifetime limit — plus how much tax you save compared to a taxable account.
What this NISA simulator estimates
NISA is Japan’s tax-exempt investment account, renewed in 2024 with two parallel allowances: the accumulation allowance, capped at 1.2 million yen a year, and the growth allowance, capped at 2.4 million yen a year. This simulator takes your monthly contribution to the first, your annual lump sum into the second, an assumed rate of return and a number of years, and works out what the holding would be worth — applying both the annual caps and the lifetime tax-free limit of 18 million yen, of which at most 12 million may sit in the growth allowance.
The renewed scheme removed the time limit on holding assets tax-free and allows both allowances to be used at once. What the rules alone do not make obvious is how quickly a given monthly contribution consumes the lifetime limit, or how combining lump sums with regular contributions changes the outcome — you really have to put numbers in. This tool shows the pace at which the allowances fill up and, alongside it, the difference against holding the same investment in a taxable account, which is a reasonable proxy for the tax you save.
Sources used in this calculation
Statutory figures such as tax and insurance rates come from the public bodies listed below. They change when the law is revised, so please also check the primary source before relying on the result for an important decision.
- NISA annual investment allowances and lifetime tax-free holding limit — Financial Services Agency (金融庁) Effective from 2024-01 ／ Last checked 2026-09-18
- Tax rate on capital gains from listed shares (income, reconstruction surtax and resident tax) — National Tax Agency (国税庁) Effective 2013-01 to 2047-12 ／ Last checked 2026-09-18
How to use the simulator
- Enter the monthly amount for the accumulation allowance The ceiling is 100,000 yen a month, or 1.2 million a year. Set anything from zero upwards with the slider or by typing a figure.
- Enter the annual amount for the growth allowance The ceiling here is 2.4 million yen a year, and the calculation assumes a lump sum invested at the start of the year. It can be used alongside the accumulation allowance.
- Enter the assumed annual return For a long-term fund, somewhere between 3 and 7 per cent is a reasonable range. It is worth trying both an optimistic and a conservative figure.
- Enter the number of years Anything from 1 to 50 years. A longer horizon makes it easier to see in which year the lifetime limit is reached.
- Review the result and the chart The final value, the investment gain and the comparison against a taxable account are shown, with a chart of how the value develops and a year-by-year breakdown table.
Tips for getting more out of it
- Using only the Tsumitate Quota at its max pace (100,000 JPY/month, 1,200,000 JPY/year) takes 15 years to fill the 18,000,000 JPY lifetime limit. Combining it with the Growth Quota fills the limit faster.
- Try several expected-return scenarios — both optimistic and conservative — to get a feel for the range of outcomes before committing to a plan.
- The gap between "NISA balance" and "if held in a taxable account" in this tool is a rough estimate of the tax benefit of using NISA.
- Unused annual quota (1,200,000 JPY Tsumitate / 2,400,000 JPY Growth) does not carry over to the next year. Investing consistently each year makes the most of your available quota.
When this simulator is useful
Deciding how much to put aside for retirement
Vary the monthly amount and the number of years to see whether you reach the sum you will need by the time you stop working. For a figure grounded in living costs and pension income, the retirement savings calculator gives a more precise target.
Moving from the old Tsumitate NISA to the new scheme
Compare the final value at the same return and horizon between the old annual allowance of 400,000 yen and the new 1.2 million. Note also that holdings in the old NISA sit outside the new lifetime limit, which affects how you plan.
Investing a bonus through the growth allowance
Set the accumulation allowance to zero and fill in only the growth allowance to model a single annual lump sum. Comparing that with a combined pattern shows how differently the allowances fill.
Seeing how much the tax exemption is worth
The tool displays alongside it what the same contributions and return would yield in a taxable account, where gains are taxed at 20.315 per cent, so the benefit appears as a figure. For general compound interest, the investment return calculator covers the same ground more broadly.
Terms used with the new NISA
- Accumulation allowance (つみたて投資枠)
- A tax-free allowance covering designated funds and ETFs suited to long-term, regular, diversified investing. The annual cap is 1.2 million yen, equivalent to 100,000 a month, which suits contributing a fixed amount each month.
- Growth allowance (成長投資枠)
- A tax-free allowance with a wider range of eligible products, including listed shares and funds. The annual cap is 2.4 million yen and it can take lump sums. It may be used at the same time as the accumulation allowance.
- Lifetime tax-free limit
- The ceiling on what you can hold tax-free across both allowances over your lifetime: 18 million yen, of which at most 12 million may be in the growth allowance. Selling restores allowance from the following year onwards.
- Unlimited holding period
- Under the old NISA up to 2023, tax-free holding was time-limited — five years for the general NISA, twenty for Tsumitate NISA. The new scheme removes that limit, so gains stay untaxed until you sell.
- Restoration of the lifetime allowance
- When you sell a holding in a NISA account, the lifetime limit is restored from the following year by the purchase price, or book value, of what you sold. The annual cap itself does not reset, so the room cannot be reused within the same year.
- Capital gains tax (20.315%)
- The rate applied to profits from selling funds or shares in a taxable account. It comprises 15% income tax, 0.315% special reconstruction income tax and 5% resident tax; gains inside a NISA account are not subject to it.
FAQ
Side Note — Where the Name "NISA" Comes From, and How the New System Differs
The name NISA (Nippon Individual Savings Account) was coined by prefixing the "N" for Nippon (Japan) onto the UK's Individual Savings Account (ISA) scheme, which has existed there since 1999. Japan launched its own version of the tax-free small investment scheme in 2014, and it has gone through several revisions since.
The New NISA, launched in 2024, made its biggest change by removing the old system's limited holding periods (5 years for General NISA, 20 years for Tsumitate NISA) — the tax-free holding period is now unlimited. Another major change: under the old system you had to choose either General NISA or Tsumitate NISA, but the New NISA lets you use both quotas simultaneously, and the annual Tsumitate limit was tripled from 400,000 JPY to 1,200,000 JPY.
According to Japan's Financial Services Agency, account openings and purchase volumes rose sharply after the New NISA launched, suggesting the policy goal of shifting household savings into investment is gaining some traction. That said, the tax-free benefit does not eliminate the underlying risk of loss — most advisors suggest that steadily investing an amount that matches your personal risk tolerance matters more for long-term wealth building than rushing to fill the lifetime quota.