This egg size substitution chart is a quick guide for swapping out different size eggs. This chart uses the U.S. large egg as the foundation for the conversion because they are the most common sized called for in modern U.S. recipes. I’ll be honest here for the larger eggs (Large, Extra-Large, and Jumbo) I just go with 1 to 1. For smaller eggs (medium, Small and Peewee) I round up to the next whole egg. I’ve never noticed any harm in doing this. However, if precision is your thing, I have kept a decimal place in the chart and you can choose how to handle them.