An apparatus for estimating blood pressure, comprising: a pulse wave sensor configured to measure a pulse wave signal from an object; and a processor configured to: obtain a first feature and a heart rate based on the pulse wave signal, the first feature comprising a ratio between a first amplitude at a first time point and a second amplitude at a second time point in the pulse wave signal, estimate a mean arterial pressure, MAP, and a pulse pressure, PP, based on the first feature and the heart rate, estimate a first blood pressure based on the MAP and the PP, obtain one or more second features based on the pulse wave signal, the one or more second features comprising a ratio between an amplitude at a maximum point of the pulse wave signal and an area of the pulse wave signal, and/or a ratio between an amplitude at a point of a first reflection wave and an amplitude at a point of a propagation wave among component waveforms constituting unit waveforms of the pulse wave signal, and estimate a second blood pressure by using the one or more second features, wherein the processor is further configured to determine reliability in estimating blood pressure based on directions of changes in the first blood pressure and the second blood pressure compared to a calibration time, obtain a third blood pressure based on the determined reliability by using at least one of the first blood pressure and the second blood pressure, and output the obtained third plod pressure as a final blood pressure. a pulse wave sensor configured to measure a pulse wave signal from an object; and a processor configured to: obtain a first feature and a heart rate based on the pulse wave signal, the first feature comprising a ratio between a first amplitude at a first time point and a second amplitude at a second time point in the pulse wave signal, estimate a mean arterial pressure, MAP, and a pulse pressure, PP, based on the first feature and the heart rate, estimate a first blood pressure based on the MAP and the PP, obtain one or more second features based on the pulse wave signal, the one or more second features comprising a ratio between an amplitude at a maximum point of the pulse wave signal and an area of the pulse wave signal, and/or a ratio between an amplitude at a point of a first reflection wave and an amplitude at a point of a propagation wave among component waveforms constituting unit waveforms of the pulse wave signal, and estimate a second blood pressure by using the one or more second features, obtain a first feature and a heart rate based on the pulse wave signal, the first feature comprising a ratio between a first amplitude at a first time point and a second amplitude at a second time point in the pulse wave signal, estimate a mean arterial pressure, MAP, and a pulse pressure, PP, based on the first feature and the heart rate, estimate a first blood pressure based on the MAP and the PP, obtain one or more second features based on the pulse wave signal, the one or more second features comprising a ratio between an amplitude at a maximum point of the pulse wave signal and an area of the pulse wave signal, and/or a ratio between an amplitude at a point of a first reflection wave and an amplitude at a point of a propagation wave among component waveforms constituting unit waveforms of the pulse wave signal, and estimate a second blood pressure by using the one or more second features, wherein the processor is further configured to determine reliability in estimating blood pressure based on directions of changes in the first blood pressure and the second blood pressure compared to a calibration time, obtain a third blood pressure based on the determined reliability by using at least one of the first blood pressure and the second blood pressure, and output the obtained third plod pressure as a final blood pressure. <EOS>