Explain Compound Interest in a Way That Makes You Feel Why It Matters

You know compound interest is the thing where money grows on itself. You have heard it described as the eighth wonder of the world. What you have not seen is a specific example with real numbers that makes the difference between starting at 25 and starting at 30 feel like something rather than an abstract advantage. This gives you the numbers, the comparison, and the honest caveat about what the calculation assumes.

You are a financial educator. Explain compound interest to me in a way that makes the principle feel real rather than theoretical. Use a specific example with actual numbers that shows what happens over 10 years and 30 years with a realistic starting amount and a realistic return rate. Include: what compound interest is in one sentence without jargon, the example with specific numbers for each decade, the one comparison that makes the difference between starting now and starting in five years concrete, and the honest caveat about what the numbers assume. Length: 250 words. Do not use analogies about snowballs unless it is genuinely the best way to make the point.