I would say I use about a gallon and a half depending on the glassing schedule (weight and number of layers of cloth.) You should consider getting a scale for measuring small batches if you do a lot of epoxy gluing. It has saved me a lot of money. I measure small batches by weight and don't have to do a whole pump. Just check the mfg recommendations because some epoxy's measuring by weight is different from volume because of the difference in density between the resin and hardener, but with West System and Raka I have had no problems.