ROI and CAGR Calculator
Enter a starting value and an ending value and get the total gain, the ROI percentage, and the CAGR - the annual rate that would have produced the same result.
Formula and method
Total gain: ending value minus starting value. Nothing clever here.
ROI: ((end − start) ÷ start) × 100.
CAGR: ((end ÷ start) 1/years − 1) × 100. Only defined for positive values over a positive period, since it involves taking a root.
Worked example
A holding bought for €100 is worth €150 two years later.
ROI = ((150 − 100) ÷ 100) × 100 = 50%.
CAGR = ((150 ÷ 100) 1/2 − 1) × 100 ≈ 22.47% a year. That's less than half of 50%, because the second year's growth compounds on top of the first.
FAQ
Frequently asked questions
What's the actual difference between ROI and CAGR?
ROI is the total percentage return over the whole period, full stop. CAGR is the constant annual rate that would have gotten you there, which is what lets you compare periods of different lengths fairly.
What's the CAGR formula?
CAGR = ((end ÷ start) ^ (1 ÷ years) − 1) × 100. €100 growing to €150 over two years works out to a CAGR of about 22.47%.
Why does CAGR come back blank sometimes?
The formula takes a root of the ratio between the two values, so it needs a positive start, a positive end and a period longer than zero to mean anything.
What about money added or taken out during the period?
Leave it out. ROI and CAGR only compare two point-in-time values. If cash moved in or out along the way, use a money-weighted measure like IRR instead.
Do dividends count?
Only if you've folded them into the ending value. Use the total value, including reinvested income, if you want a total-return figure.
More free tools