Model monthly and yearly contributions against New NISA allowances, factor in an expected return, trust fee, and taxable gains, and visualise the tax-free advantage with allowance usage year by year.
Value projection
Annual allowance usage
The taxable scenario subtracts the specified tax rate from gains to show the after-tax value.
FAQ
Can I adjust the allowance values?
Yes. Edit the annual and lifetime allowance fields to match future revisions or alternative limits for your simulation.
How are fees and taxes applied?
The trust fee is deducted from the annual return before compounding. Taxable accounts apply the selected tax rate (20.315% by default) to gains at the end of the period.
Which inputs define the comparison?
Set the monthly contribution, expected annual return, investment period, annual allowance, lifetime allowance, and trust fee. Then compare the New NISA and taxable scenarios.
Why is 20.315% used as the default tax rate?
It reflects the standard Japanese tax rate on listed investment gains. Edit the field if your planning case uses a different rate or future rule assumption.
How should I read allowance usage?
The breakdown shows how contributions fill the annual and lifetime New NISA limits. Amounts above the allowance are compared as taxable investments.
How to compare New NISA and taxable investing
What this simulator does
This page estimates a JPY investment plan inside Japan's New NISA allowance and compares it with a taxable account using the selected tax rate.
Inputs to review
Monthly contribution, annual return, investment period, trust fee, annual allowance, lifetime allowance, and tax rate all change the final comparison.
Allowance logic
The simulator fills the annual and lifetime New NISA allowance first. Contributions that exceed those caps are treated as taxable for comparison.
Common mistakes to avoid
Do not treat the tax-free advantage as guaranteed profit. Returns, fees, contribution timing, and future rule changes can all affect the result.
Interpretation guidance
Use the chart and allowance breakdown to see whether the contribution plan fits within the limits and how much tax drag appears in the taxable scenario.