Leather clog sizing guide
Understand size conversions, width and comfortable fit.
Measure both feet in the afternoon while standing and use the longer measurement. Compare the result against the actual manufacturer's chart, not an unrelated size conversion chart.
European, UK and US sizes are not perfectly interchangeable between brands. Unisex styles may display two US equivalents for the same shoe, so the EU size can be a useful reference.
Check the width of the toe box and instep height. An open-back clog should remain reasonably secure without forcing your toes to grip. Adjustable straps may help with volume, but they cannot fix a shoe that is too narrow.
Try footwear indoors on a clean floor until you are confident about size, and confirm the retailer's terms for returns and exchanges.