Adaptive payload monitoring system

A payload monitoring system (50) for an excavation machine (10) is disclosed. The payload monitoring system may have a tool (16), a first sensor (64) configured to generate a first signal indicative of a velocity of the tool, and a second sensor (62B) configured to generate a second signal indicative of a lift force of the tool. The payload monitoring system may also have a controller (60) in communication with the first sensor and the second sensor. The controller may be configured to record the velocity and the lift force of the tool during a work cycle based on the first and second signals, and partition the work cycle into a plurality of segments including a loaded moving segment. The controller may also be configured to determine a period of time within the loaded moving segment during which the velocity of the tool is substantially constant, and calculate a payload of the tool based on the lift force recorded during the period of time.