Which has the biggest impact on a DCF: Revenue, COGS, or CapEx — and why?

Answer

CapEx, then COGS, then Revenue. The closer a line item sits to the FCF line (bottom), the bigger its dollar-for-dollar impact. CapEx flows directly into FCF as a subtraction. COGS hits EBIT and then flows to FCF after taxes. Revenue sits at the top — it has to pass through variable costs, gross margin, operating margin, and tax before reaching FCF.