This document discusses three ways to measure happiness: experienced wellbeing by evaluating past experiences, eudemonic wellbeing by assessing self-worth and purpose, and evaluative measures through life satisfaction surveys. It notes that experienced wellbeing can predict future behavior, eudemonic wellbeing explains motivations, and evaluative measures are useful for policy by revealing areas people feel they are thriving or lacking. It encourages counting happiness through a survey on the website happycounts.org.