The energy spectrum of ultra-high energy cosmic rays measured using the Pierre Auger Observatory is presented. The measurements benefit from the huge exposure of approximately 80000 km$^2$ sr yr achieved in 14 years of data taking with a surface-detector array that extends over 3000 km$^2$ having 1600 detectors on a 1500 m spacing, and from the almost-calorimetric estimation of the energy scale provided by the fluorescence detector.
In this contribution, we address recent improvements in the measured spectrum at energies above 3 EeV using events with zenith angles less than $60^\circ$. These improvements concern the estimation of the shower energy and its resolution. Further, we report on updates of the energy spectra derived from other independent and complementary data sets, namely from showers with larger zenith angles, those detected by a smaller and denser array with 750 m spacing, and those detected by the fluorescence detector, together with the recent extension of the flux measurements to lower energies using atmospheric Cherenkov radiation.