What CAGR measures
The compound annual growth rate is the single yearly rate that would take a value from its start to its end over a period, as if it grew smoothly. It removes the year-to-year noise so you can compare growth fairly.
The CAGR formula
CAGR = (Ending ÷ Beginning)^(1 ÷ Years) − 1. Growing $100 to $200 over four years is a CAGR of about 18.9%, even if the path there was bumpy.
Using CAGR in cases
Growth questions are everywhere in consulting and finance interviews. Stating a clean CAGR shows you can translate a before-and-after into an annual rate on the spot.