A method and apparatus for calibrating a pipelined analog-to-digital converter (ADC) is disclosed. A method includes reading a first output level from a first sub-ADC, reading one or more additional output levels from one or more additional sub-ADCs, combining the one or more additional output levels from the one or more additional sub-ADCs into a combined output level, and adjusting a comparator threshold of the first sub-ADC when the first output level and the combined output level meet a set of predetermined conditions.