ROI Calculator

💰 How This Calculator Works

Calculates Return on Investment as a percentage of the original investment cost.

🔢 Worked Examples

• Buy at $10k, sell at $14k → ROI = 40%
• Campaign cost $5k, revenue $20k → ROI = 300%
• Consider: 40% over 5yr vs 40% over 1yr are very different annualised

📋 Common Use Cases

Savings calculators project how regular contributions and compound interest build wealth over time. Starting early is the single most powerful lever — thanks to compound growth, money saved at 25 can be worth 8× more at retirement than money saved at 45.

• Setting a monthly savings target to reach a goal by a deadline
• Comparing different savings account rates
• Planning a down payment for a home or car
• Modelling retirement savings by age

💡 Did You Know?

The "latte factor" coined by David Bach: saving $5/day from age 25 to 65 at 8% annual return grows to over $520,000. The math is unforgiving in both directions — for saving and for spending.

⚠️ Common Mistake

Not annualising ROI — a 40% return over 5 years is only 6.96% annually. Always convert to annualised ROI (CAGR) for fair comparison across different time periods.