複利計算ツール
初期資金と定期積立がどのように増えうるかを試算し、結果のうち自己拠出分と複利による増加分の内訳を確認できます。利回りはご自身で設定する仮定であり、予測ではありません。
- 予測残高
- $300,851
- 自己拠出額
- $130,000
- 複利による増加分
- $170,851
年ごとの残高 — 濃い部分が自己拠出分です
1 年目20 年目
計算方法
balance = start x (1 + r)^n + PMT x [((1 + r)^n - 1) / r]
- r
- annual return / 12 (this tool compounds monthly)
- n
- number of months
- PMT
- contribution added at the end of each month
計算例
$10,000 plus $500 a month at 7% for 20 years reaches about $301,000. Of that, $130,000 is money you paid in and roughly $171,000 is compounding — the split matters more than the headline.
よくある質問
- How does compound interest work?
- Each period’s return is calculated on the balance including previously earned returns, so growth accelerates over time. The formula here compounds monthly and adds your contribution at the end of each month.
- What rate of return should I assume?
- Any rate you enter is an assumption, not a forecast. Real returns vary year to year and can be negative. Because the projection compounds, small changes in the rate produce large changes at long horizons — try a range rather than a single figure.
- Does this account for inflation, tax or fees?
- No. The result is a nominal projection before inflation, taxes and any platform or fund fees, each of which reduces what you actually keep. Treat it as arithmetic on your inputs rather than an expected outcome.
その他の無料ツール
このツールは入力された数値を計算するものです。情報提供および教育目的のみであり、投資・税務・財務上の助言ではなく、いかなる証券の売買や保有を推奨するものでもありません。試算は仮定であって予測ではありません。必ずご自身で十分に確認してください。