A big challenge is to know "What size do I buy for myself or my child?"
Keeping in mind that this is a guideline.
I recommend using the "General" Sizing Chart and look at the size you normally wear.
Then take a look at the actual garment sizing chart and check the measurements against it.
When measuring it is always best to use a clothing tape measure.
I would recommend leaning on the larger side if you fall at the top end of the chart.
This information is intended for use as a general guideline. Sizing and fit may vary somewhat by brand. All measurements are in inches.