Professional Guide
ROI, CAGR and Break-Even: A Finance Guide for Non-Finance Professionals
How to evaluate an investment with return on investment, compound annual growth rate and break-even analysis — the three numbers that make a business case credible.
Every business case comes down to a few numbers: what it returns, how fast it grows, and how much volume it needs to stop losing money. ROI, CAGR and break-even analysis answer those three questions.
This guide defines each metric, shows the formula, and explains the common mistakes that make business cases misleading.
Return on investment (ROI)
ROI measures the return relative to the amount invested: ROI = net gain ÷ cost of investment, usually expressed as a percentage. The PanelRoster ROI calculator takes the investment and the return (or net gain) and returns the ROI percentage.
ROI is only as good as the cash flows behind it. It ignores timing and risk, so it is a screen, not a complete evaluation — pair it with payback period and NPV where material.
Compound annual growth rate (CAGR)
CAGR is the constant annual growth rate that would turn a starting value into an ending value over a number of years: CAGR = (end ÷ start)^(1/years) − 1. It smooths year-to-year volatility into a single comparable rate, which is why it is used for revenue growth and long-run investment returns.
The CAGR calculator takes start value, end value and years and returns the CAGR. Be careful with negative or zero start values — CAGR is not meaningful there.
Break-even analysis
Break-even is the volume at which revenue equals total cost (fixed plus variable): break-even units = fixed costs ÷ (price per unit − variable cost per unit). The break-even calculator returns the units needed to cover costs, given price, fixed costs and variable cost.
Break-even is a powerful framing for pricing and volume decisions: it shows how much buffer you have and what a price or cost change does to it.
Key takeaways
- ROI = net gain ÷ investment; a screen, not a complete evaluation.
- CAGR = (end÷start)^(1/years) − 1 — the smoothed annual growth rate.
- Break-even units = fixed costs ÷ contribution margin per unit.
- Use all three together to make a business case defensible.
Tools used in this guide
Related guides
References
References are provided for further reading; PanelRoster is not affiliated with the linked resources.