The plating-out film thickness during rolling in cold rolling with emulsion is quantitatively estimated for the improvement of productivity and the precise control of surface qualities after rolling. The estimating method of the plating-out film thickness was investigated using the numerical method of the inlet oil film thickness under the starvation condition of emulsion. The estimation model was proposed using a new starvation model considering the plating-out film on the roll and strip surface proposed by Azushima, et al. Sheets and coil sheets of aluminum A1050H and mineral oil with a viscosity of 0.235 Pa center dot s were used. It is reasonable that the value of trapping ratio in the sheet rolling could be used as the value of the trapping ratio in the coil rolling. From the experimental results, the effect of the emulsion concentration and the emulsifier on the plating-out film thickness was examined using the numerical method. The plating-out film thickness increased with increasing emulsion concentration and the plating-out film thickness was relatively dependent on the affinity of the emulsion particle for the steel surface of the emulsifier.