Ah, the master mix: saving countless grad students and postdocs from pipetting-induced calluses over the years. The MasterMix app is a simple app designed to help researchers with their—yes, you guessed it—master mixes. The default recipe provided in the app is for a PCR. App users can specify the volume of each reagent and the number of reactions, and the app will then calculate the total volumes required to make the mix. This alone is not too impressive, but two additional features of the app make it handy in the lab. The first feature lets you tap on each ingredient to check it off your list (that is, if you don’t mind touching your iPhone/iPad with gloves on); the second feature lets you build a recipe library in the app. Because users are able to build their own recipes from scratch, they have the ability to easily calculate master mixes for all of their commonly used reactions, all within a single app.