The Helmholtz-Kohlrausch effect was predicted by using the CIELUV formula. The predictions were done to the chromatic colors in the whole chromaticity gamut including spectral colors by the Variable Achromatic Color (VAC) and the Variable Chromatic Color (VCC) methods. The effects of adapting-illuminance change in the perceived lightness of chromatic object colors was also taken into account in the prediction. The prediction equations by the CIELUV formula gave results quite similar to those by the equation for predicting the Helmholtz-Kohlrausch effect using the nonlinear color-appearance model. Their computational procedures for estimating various effects are very simple and easy to use.