Comfi Flat Medium Width:

US 5 / EU 36 = 7.7cm / 3"
US 6 / EU 37 = 7.9cm  / 3.1"
US 7 / EU 38 = 8.1cm / 3.2"
US 8 / EU 39 = 8.2cm / 3.23"
US 9 / EU 40 = 8.5cm / 3.3"
US 10 / EU 41 = 8.7cm 3.4"
US 11 / EU 42 = 8.9cm / 3.5"
US 12 / EU 43 = 9.2cm / 3.6"

Comfi Flat Wide Width:

US 6 / EU 37 = 9.4cm / 3.7"
US 7 / EU 38 = 9.7cm / 3.8"
US 8 / EU 39 = 10cm / 3.9"
US 9 / EU 40 = 10.3cm / 4"
US 10 / EU 41 = 10.6cm / 4.17"
US 11 / EU 42 = 10.9cm / 4.3"
US 12 / EU 43 = 11.3cm / 4.44"

How to Find Your Feet Measurements: