The electronic energy band structure, partial (PDOS) and total density of states (DOS), and linear optical properties of the paraelectric KIO3 single crystal are calculated using density functional theory (DFT) in its local density approximation (LDA). The calculated band structure for paraelectric KIO3 indicates that the crystal has a direct bandgap. Using LDA and generalized gradient approximation (GGA), structural optimization has been performed. The optical spectra of the paraelectric KIO3 in the photon energy range up to 30 eV are investigated under the scissor approximation. The real and imaginary parts of the frequency-dependent linear dielectric function, as well as related quantities such as energy-loss function, refractive index and effective number of valence electrons, are calculated. The calculated structural optimization and bandgap of the paraelectric KIO3 have been compared with experimental data and have been found to be in good agreement with the experimental results.