愛因斯坦：「複利是世界第八大奇蹟」
複利就是「利滾利」。只要時間夠長，即小的本金也能滾出巨大的財富。影響財富的三大槓桿
1. 時間: 最重要的因素。越早開始，複利效應越驚人。 2. 報酬率: * 定存: ~1-2% (雖安全但會被通膨吃掉)。 * 股票 ETF (S&P 500): 長期平均年化約 8-10%。 * 高收益債: ~4-6%。 3. 紀律: 每月固定投入 (定期定額)，克服人性追高殺低，是累積資產最穩健的方式。💰 72 法則
想知道資產翻倍需要幾年？用 72 除以年化報酬率。 * 4% 報酬: 72 / 4 = 18 年翻倍。 * 8% 報酬: 72 / 8 = 9 年翻倍。 * 12% 報酬: 72 / 12 = 6 年翻倍。常見問題
Q: 定期定額真的穩賺不賠嗎？ A: 投資皆有風險。但透過拉長時間 (10年以上) 投資大盤指數 (如 0050, VOO)，歷史數據顯示虧損機率極低。短線進出則不適用此計算機。Q: 抗通膨重要嗎？ A: 非常重要。如果您的資產增長率低於通膨率 (約 2-3%)，您的實質購買力其實在下降。
常見問題 (FAQ)
Q: Is a 7% annual return realistic for long-term investments?
A: Yes, 7% is a widely accepted inflation-adjusted (real) return estimate for diversified US stock market investments over long periods. The S&P 500 has historically returned approximately 10–10.5% annually in nominal terms (before inflation). Subtracting the Federal Reserve's 2–3% target inflation rate gives approximately 7% in real purchasing power. This is not guaranteed year-to-year—the stock market has significant short-term volatility—but over 20+ year periods, broad index fund returns have consistently been in this range.
Q: Should I invest monthly or as a lump sum?
A: If you have a lump sum available, research shows lump-sum investing outperforms dollar-cost averaging about 2/3 of the time (because markets tend to rise over time). However, for ongoing savings from a paycheck, monthly contributions are optimal—they enforce discipline and take advantage of dollar-cost averaging. If you have a windfall but are nervous about market timing, investing half immediately and half over 6 months is a reasonable compromise.
Q: How does compound interest differ from simple interest?
A: Simple interest calculates returns only on your original principal. Compound interest calculates returns on your principal plus all previously earned interest. $10,000 at 7% simple interest for 30 years = $31,000 total. $10,000 at 7% compound interest for 30 years = $76,123 total—more than double. The difference grows exponentially with time, which is why compounding is called the "eighth wonder of the world."
Q: What is the Rule of 72?
A: The Rule of 72 is a mental math shortcut: divide 72 by your annual return rate to find the approximate number of years it takes to double your money. At 7% return: 72 ÷ 7 = 10.3 years to double. At 10%: 72 ÷ 10 = 7.2 years. This works remarkably well for rates between 2% and 20%. It helps you quickly grasp the impact of different return rates without a calculator.
情境範例
72 法則的說明很淺顯易懂。看到時間拉長後的複利曲線，真的會後悔沒有早 10 年開始存錢。
介面很漂亮，計算速度很快。定時定額的模擬讓我對以後的退休生活有更精確的想像。
很好用的工具，幫我算出了存到第一個 100 萬需要多久。
Official Sources & Authority References
重要免責聲明
本計算機提供之結果僅供參考，不構成稅務、法律或財務建議。稅法每年調整，請於申報前到 IRS.gov 核實數據，或談詢具資格的稅務專業人員。
