An apparatus for non-invasively estimating blood pressure is provided. According to one embodiment, the apparatus for estimating blood pressure may include a bio-signal sensor configured to measure a bio-signal from a user and a processor configured to extract a feature from the bio-signal at an extraction time, acquire an offset based on a relative change value of the feature extracted at the extraction time, relative to a reference value of the feature obtained a time of calibration, and estimate blood pressure based on the relative change value of the extracted feature and the acquired offset.
