Apparently you did not look at it, since it gives metric sizes. The 0603 is metric 1608.is this of use
https://www.newmatik.com/knowledge-base/KB-EN-00928/resistor-case-sizes
not least , you see there are as ever a metric and a imperial system!
as Im in Europe,we use metric, measure length and width in mm,
Im sorry @BobTPHApparently you did not look at it, since it gives metric sizes. The 0603 is metric 1608.