An apparatus for estimating bio-information may include a sensor configured to obtain a bio-signal from an object, and a processor configured to obtain a second-order differential signal of the bio-signal, and extract a progressive wave component from the bio-signal using, based on a first local minimum point of the second-order differential signal being stable, the first local minimum point of the second-order differential signal, or extract the progressive wave component from the bio-signal using, based on the first local minimum point of the second-order differential signal being unstable, a maximum amplitude point in a systolic portion of the bio-signal.