So you want to know how to find ROI? Most people think investing is just about throwing money at something and hoping it goes up. But if you actually want to track whether you're making smart moves, you need to understand return on investment.

Let me break down what ROI actually is. It's basically measuring how much profit you made relative to what you spent. The formula is straightforward: take your profit, divide it by what you paid, then multiply by 100 to get a percentage. That percentage tells you the real story of your investment performance.

Here's a practical example. Say you bought 100 shares at $100 each back in early 2020, so you're in for $10,000. Fast forward to mid-2022 and you sell at $125 per share, bringing in $12,500. Your profit is $2,500. Divide that by your initial $10,000 and you get 0.25, or 25% ROI over that period. That's solid growth.

But not every investment works out. I've seen plenty of people buy at the top and watch their positions crater. If those same 100 shares had dropped to $60 each by mid-2022, you'd be sitting on a $6,000 position, which means a -$4,000 loss. That's a -40% ROI. It happens. The key is knowing how to find your actual ROI so you're not just guessing about your performance.

One thing most beginners miss is that raw ROI doesn't account for time. Making 8% in two years is way better than making 10% in ten years, but if you only look at the percentage, you might get confused. That's where annualized ROI comes in. Just divide your total ROI by the number of years you held it. So 25% over 2.5 years becomes 10% annualized. Much clearer picture.

Also, don't sleep on the hidden costs. If you're buying stocks, you might pay a commission. If you're investing in something like an antique car or real estate, there are repairs, storage, maintenance fees, all that stuff. Let's say you bought a classic car for $10,000, spent $7,500 fixing it up, and paid $2,500 to store it properly. Your actual investment cost is $20,000, not $10,000. When you sell it for $50,000, your real ROI is 150%, not 300%. That's the difference between understanding your actual returns and living in fantasy land.

When you're comparing different investment opportunities, how to find which one makes sense comes down to calculating expected ROI on each one. Say you're choosing between two stocks with $10,000 to invest. Stock A is trading at $100 and you think it'll hit $150 in five years, giving you 50% total ROI or 10% annualized. Stock B is a startup at $20 per share, and you think it could hit $100 in ten years, which would be 400% total or 40% annualized. On paper, B looks better. But B is riskier and unproven. If A takes off and hits $150 in one year instead, suddenly that's 50% annualized, which crushes B. The math helps, but you still need to think about risk.

When it's time to clean up your portfolio, ROI is your best friend. Investments consistently delivering solid annualized returns? Keep them. The ones dragging down your performance or stuck in negative territory? Those are candidates to cut loose. Just make sure you're not making decisions on ROI alone. Context matters.

Bottom line: if you want to be serious about investing, you need to track your actual performance. Knowing how to find ROI on your past investments tells you whether you're actually winning or just fooling yourself. It's the difference between investing with your eyes open and just hoping something works out.