What APM measures in real-time strategy
APM, or actions per minute, counts the keyboard and mouse inputs a player issues each minute in real-time strategy games such as StarCraft. It captures how much a player is doing: issuing commands, selecting units, building, scouting, and managing multiple bases at once. In fast games like StarCraft, high APM lets a player control many things in parallel under time pressure.
Professional StarCraft players are well known for sustaining very high APM, frequently in the range of 300 or more, while skilled amateurs commonly sit around 150 to 200 and average ladder players are much lower, often in the tens.
Why raw APM is not the whole story
A large share of pro APM consists of fast repeated inputs, sometimes called spam, used to keep the hands warm and maintain rhythm. The more meaningful measure is effective APM (EPM), which counts only actions that change the game state, filtering out redundant clicks.
What separates top players is not just speed but the quality and timing of decisions, efficient use of hotkeys and control groups, and the ability to direct attention across the map. High APM amplifies good decisions but does not replace them.