Sizing - Trunks

All measurements are of the garment, and are approximate

- You want them stretched  to stay on. 

Size Waist
2T 12.5"
4 14"
6 15"
8 17"
10 18.5"
12 20.5"

Note the 195gsm merino has about a 40% stretch factor - so 12.5" waist can stretch to approx 17.5"