First sizing: my feet are 25.4cm long x 10cm wide and I have a high arch. I am usually eu 40 in Birkenstocks, uk 6.5 in Dr Martens, us 8.5 in Butora Gomis. I bought a w10/m9 in the clogs, I size up. Because of the high arch, I have had to adjust it the front straps to the smallest option. I’m still working on getting the back adjustment right for my narrow heel. Overall, the length size is right and the width works, but definitely is roomy for a narrower foot. The clogs are intended to be a durable replacement for my aging Birkenstocks. They are definitely a style choice, but given their practicality I’m happy with that choice.
This stuff is delicious. Don't take my word for it- get a bottle, you won't regret it