An upscaling technique is developed for acoustic measurements on cores to present core data as a log for improved comparison between laboratory and sonic measurements. The method combines a laboratory study performed over a wide range of frequency, pressure, and saturation conditions on a series of core samples and construction of a synthetic log that includes upscaling of core measurements at the sonic wavelength and simulation of the log response for various spacing of the tool receivers. A comparison of core and sonic measurements in a carbonate reservoir illustrates the benefit of comparing core and log measurements at the same scale. Agreement between punctual core and sonic measurements is within +/- 10%, whereas core data upscaled at the level of sonic measurements are within +/- 2% of the sonic. In addition, results of quantitative interpretation of the sonic data in terms of porosity also confirm that sonic measurements can provide accurate estimates of petrophysical properties when properly calibrated with core data.