What is the CAGR if an investment grew from 10,000 to 30,000 in 8 years?

Based on these numbers, the CAGR (compound annual growth rate) is about 14.72% per year.

8 years

What is CAGR?

CAGR (Compound Annual Growth Rate) is the constant annual rate at which a single investment would need to grow to go from its beginning value to its ending value over a given period — it assumes one entry and one exit, unlike XIRR which handles multiple cash flows.