ROI vs Annualized Return (CAGR)
Why a 50 percent total ROI over five years is not 50 percent a year, how CAGR restates returns per year, and when to trust each number.
Total ROI in a single number
Total ROI answers a simple question: for every dollar you put in, how much did you get back? It is the net return divided by the original cost, shown as a percentage, so a $1,000 investment worth $1,500 has a 50 percent ROI. That simplicity is its strength for quick comparisons and its weakness for anything time-sensitive. On its own, ROI says nothing about how long the money was tied up.
Why time changes the story
A 50 percent gain earned in one year is excellent; the same 50 percent spread over ten years is modest. Total ROI cannot tell those apart because it collapses the whole period into one figure. That is a problem when you want to compare a quick flip against a long hold, or a stock against a savings account. To rank investments fairly you need a rate that accounts for the number of years involved.
How CAGR levels the field
Compound annual growth rate, or CAGR, restates a total return as the steady yearly rate that would have produced it. The formula is (final value divided by cost) raised to the power of one over the number of years, minus one. For $1,000 growing to $1,500 over two years, that works out to about 22.47 percent a year. Because it is a per-year rate, CAGR lets you compare a two-year holding directly against a five- or ten-year one.
What both numbers still miss
Neither ROI nor CAGR captures taxes on your gains, brokerage or fund fees, or the way inflation erodes purchasing power over time. They also ignore risk, so a wild ride and a smooth climb to the same endpoint look identical. Use them to size and compare returns, then adjust for costs and taxes separately before deciding whether a result is actually good.