UGG boots run big. It is important to buy a whole or half size smaller but it mainly depends on your foot width . So if you are an 8 or 1/2 and a medium width then buy an 8. Also if you are a 9 narrow then buy an 8.

Should I size up or down for UGGs?

UGGs generally fit true to size. However, you want your new UGGs to be snug. Overtime the inner with begin to flatten and mould to your foot making them a little roomier, so your fresh UGGs need to be tight to the foot to account for this. The best way to check your size is to measure them!

Do UGGs come in 1/2 sizes?

Some of their fashion boots and snow boots come in half sizes. They have styles and sizes for the whole family, from infants through to adults. The sizing charts for all Ugg boots can be found here. As well as sizes for the US and other countries, they give you a length in inches for each size.