ROI計算機
投資収益率と年間リターンを計算
純利益
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ROI
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年間ROI
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使い方
値を入力
入力フィールドに数値やパラメータを入力します。
即座に結果を取得
入力するとすぐに結果が更新されます — 送信ボタンは不要です。
コピーまたは保存
結果をクリップボードにコピーするか、ワークフローで活用します。
このツールを使う理由
完全無料
隠れたコストもプレミアムプランもありません — すべての機能が無料です。
インストール不要
すべてブラウザで実行されます。ソフトウェアのダウンロードやインストールは不要です。
プライベート＆安全
データはデバイスの外に出ることはありません。サーバーにアップロードされることはありません。
モバイル対応
完全レスポンシブ対応 — スマートフォン、タブレット、デスクトップで利用できます。
Return on Investment (ROI) is a fundamental metric for evaluating the profitability of any investment or business decision. It helps you compare different opportunities on equal footing.
Key Concepts
Simple ROI
ROI = (Net Profit / Cost of Investment) × 100%. A straightforward way to measure profitability, but it doesn't account for the time period of the investment.
Annualized Return
To compare investments held for different periods, annualize the return. A 50% return over 5 years is roughly 8.4% annualized — much different from a 50% return in 1 year.
Risk-Adjusted Return
Higher returns usually come with higher risk. Two investments with the same ROI but different risk profiles are not equivalent. Consider volatility and downside potential.
Opportunity Cost
The true cost of an investment includes what you gave up by not choosing the next best alternative. A 5% ROI isn't attractive if a risk-free savings account yields 4.5%.
Practical Tips
Always include all costs (fees, taxes, maintenance) when calculating ROI — hidden costs can significantly reduce your actual return.
Compare ROI across similar time horizons and risk levels for meaningful comparisons.
Don't chase high ROI without considering the associated risks — sustainable, moderate returns often outperform volatile high returns over time.
Diversify your investments to balance overall portfolio risk rather than concentrating everything in the highest-ROI option.
This content is for educational purposes only and does not constitute investment advice. Past performance does not guarantee future results. Consult a qualified financial advisor before making investment decisions.