A universal fluid transfer device is disclosed for transferring fluid from a first container to another utilizing gravity feed. The device comprises a first and second container-connecting cap adapted to securely connect to a receiving and emptying container opening, respectively. The caps preferably threadably engage each container opening, while a central transfer channel threadably connects to each cap to effectuate a path for fluid transfer therebetween. A plurality of cap sizes can be utilized in conjunction with the fluid transfer channel to accommodate various container opening sizes, providing transfer of fluid between identical or dissimilar container openings using a single device that can modularly adapt to different dimensions.