How to Measure a Kezayis?

What is the correct way to measure a kezayis?

We’ve previously addressed the question of what constitutes the shiur (halachic measurement) of a kezayis (the size of an olive), and noted that there is a machlokes (difference of opinion among poskim) whether it’s the volume of half an egg or somewhat less than a third of an egg. (We always follow the more stringent measurement, which is usually the large one.)

It’s important to note that these shiurim are measurement of volume, not of weight. Contemporary seforim that quote amounts by units of weight have converted the original shiur of volume into the approximate equivalent in weight to make measuring easier. Those who don’t wish to rely on those approximations and wish to measure the volume of an item should be aware of the following: if there is a large hollow space inside the item, it should not be included in the measurement, whereas puffiness, fluffiness and sponginess are considered part of the volume, and should be included. #537?1

https://halacha2go.com?number=537

Practical Halacha: One minute a day. By Horav Yosef Yeshaya Braun, shlita, Mara D'asra and member of the Badatz of Crown Heights.