Jason Johns > Quotes

“Firstly, dig down to level ten; the coordinates of which will be something like “feet 10.00 eyes 11.62”. Then dig to your left and right until you have coordinates at each end which can be divided by 16, e.g. 144 at one end and 160 at the other. All blocks between these two ends are a chunk. Repeat the same for the z axis and you will have marked out a complete chunk. Once you have calculated the first one, it is easy to work out the rest as you can just count 16 blocks.”
― Jason Johns, Ultimate Minecraft - The Complete Guide To Mining And Finding Ores