K-correction calculations directly affect the Type Ia supernovae (SNe Ia) magnitude determination and therefore directly affect the determination of cosmological parameters. The intrinsic variations in the colours and the spectral features of SNe Ia complicate the k-correction calculations and introduce uncertainties. We gathered available flux-calibrated spectra of local SNe Ia. The k-corrections calculated using a local supernova spectrum are compared with the k-corrections calculated using a supernova template spectrum of the same epoch. The difference comparison provides a way to quantify the k-correction errors. Because the intrinsic colour of a high redshift supernova can be inferred from its stretch parameter, the supernova template spectrum is %93mangled%94 to have the same colour as the local spectrum for each epoch. We show that the errors can be reduced by using the %93mangled%94 template spectra for k-correction calculations.