We present data of the coefficient of band-to-band absorption of crystalline silicon at 295 K in the wavelength range from 950 to 1350 nm and analyze its uncertainty. The data is obtained from measurements of reflectance and transmittance as well as spectrally resolved photoluminescence measurements and spectral response measurements. A rigorous measurement uncertainty analysis based on an extensive characterization of our setups is carried out. We determine relative uncertainties of 4% at 1000 nm, increasing to 22% at 1200 nm and 160% at 1300 nm, and show that all methods yield comparable results. © 2014 AIP Publishing LLC.