A computer program is described which calculates volumes of individual formulations when mixing single or multiple compounds within a single mixture. Calculations are based on a fixed volume of carrier, and compensate for increased volume realized by the addition of insecticides. Error obtained from this program as compared with actual mixtures in volumetric flasks was generally less than 0.09% for each of 5 compounds representing emulsifiable concentrates, a soluble liquid and a microencapsulated flowable formulation, each at 2 rates. Use of this program provides for the use of automated carrier measuring devices, saves time, and reduces possibility of error in field mixing where it is impractical to add carrier to the proper amount of insecticide until the desired volume is reached.