Compound interest is the return you earn not just on the money you originally invested, but also on the returns that money has already generated — so your gains start producing gains of their own. Over long periods this "interest on interest" is what turns steady saving into meaningful wealth.
Because each year's growth is calculated on a bigger base than the year before, the curve bends upward the longer you stay invested. The practical takeaway for a first-time investor: the number of years you let money compound is usually a bigger lever than chasing a marginally higher return. Starting at 22 instead of 32 gives compounding ten extra years to work — often worth more than the entire amount you contribute in your 30s.
No. Compounding describes the arithmetic of growth on growth, but the growth rate itself is never guaranteed — a negative year compounds downward too, and markets can fall for years at a time. Any projected rate is an assumption, not a promise.
For a first-time investor, time is usually the bigger lever. Because each year's growth is calculated on a larger base, extra years often add more to the final total than a slightly higher rate would — which is why starting early matters so much.
Simple interest is paid only on the original amount, so it grows in a straight line. Compound interest is paid on the original amount plus all prior returns, so it grows in a curve that steepens over time.
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Educational research only — not investment advice.