複利計算機
投資の複利効果を計算。定期的な積立とともに資産の成長を確認。
Enter your investment details and click Calculate to see how your money grows.
Frequently Asked Questions
How does compound interest work?
Compound interest earns interest on your interest. If you invest $1,000 at 7% annually, after year 1 you have $1,070. Year 2 you earn 7% on $1,070 (not just the original $1,000). Over decades, this snowballs dramatically.
How much should I invest monthly to become a millionaire?
Investing $500/month at 7% annual return for 35 years gives you about $900,000. Increasing to $600/month gets you over $1 million. Start early — time is the most powerful factor in compound growth.
What's a realistic annual return to expect?
The S&P 500 has historically returned about 10% annually before inflation, or about 7% after inflation. Our calculator defaults to 7%. Conservative estimates use 5-6%; optimistic use 8-10%.