๐น NISA / DCA Investment Simulator
Enter your monthly contribution amount, expected annual return, and investment period to simulate the total principal, investment gain, and final value of a regular (dollar-cost averaging) investment plan such as tsumitate NISA.
How to use
- Enter the monthly contribution amount.
- Enter the expected annual return.
- Enter the investment period in years.
- Total principal, investment gain, and final estimated value are calculated automatically.
How the calculation works
This simulator assumes a fixed monthly contribution that keeps growing at a constant rate, and calculates what it would be worth in the future. With monthly rate r (annual rate รท 12), n months and monthly contribution M, the final value is M ร ((1 + r)โฟ โ 1) รท r. That is the sum of each contribution compounded over the months it has left โ the first for n โ 1 months, the second for n โ 2, and so on. Total contributions are M ร months, and the gain is final value โ total contributions. NISA, Japan's tax-free investment scheme, exempts investment gains from tax, but this simulator does not model tax or the scheme's contribution limits. It is an illustration of how regular saving and compounding add up.
Worked example
ยฅ30,000 a month at 4% for 20 years Total contributions: 30,000 ร 240 = ยฅ7,200,000 Final value: about ยฅ11,003,239 Gain: about ยฅ3,803,239 In a taxable account, gains would be taxed at about 20%, so the benefit of investing tax-free grows with the length of time and the size of the gain.
Things to be aware of
- Real investments rise and fall, so returns are never the same every year. This does not guarantee any outcome.
- NISA annual and lifetime limits, and tax, are not modelled.
- Fund fees such as expense ratios are not included; they reduce your real return.
- You can lose money. Investment decisions are your own responsibility.
FAQ
Is this simulation guaranteed to match real investment results?
No. This is only an estimate assuming the entered annual return holds steady every year. Actual market returns fluctuate and may be higher or lower than simulated.
Does this account for NISA's tax-free limits?
No. This simulator does not model NISA annual or lifetime tax-free investment limits, or any tax rules. It simply projects compound growth of regular contributions.
How is compounding calculated?
The expected annual return is converted to a monthly rate, and each month's contribution is assumed to compound at that monthly rate for the remaining months in the period.
What return rate should I assume?
There's no guarantee past performance will repeat, but many people use a reference figure around 3-5% for planning purposes. Adjust it to match your own investment outlook.
Can I compare different investment periods?
Yes โ just change the number of years and the total principal, gain, and final value recalculate, so you can compare, say, 10 years against 20 years.