估算 (gū suàn) is a verb meaning 'to estimate' or 'to calculate roughly' — that is, to arrive at an approximate value or quantity without exact measurement or detailed computation. The character 估 (gū) means 'to guess' or 'to assess preliminarily', while 算 (suàn) means 'to calculate' or 'to figure out'. Together, they emphasize a quick, practical, and often intuitive mental calculation rather than precise arithmetic. It’s commonly used in contexts involving time, cost, quantity, distance, or resource planning — especially when full data isn’t available or speed matters more than precision.

This word carries a neutral-to-formal register and appears frequently in everyday speech, business reports, academic discussions, and news articles. Unlike the more technical 计算 (jì suàn), which implies exact computation, 估算 suggests reasonable approximation grounded in experience or observation. It can be used both transitively (e.g., 估算成本) and intransitively (e.g., 我们需要先估算一下), often followed by 一下 for softening or 了 to indicate completion.