Demonia boot and shoe sizing runs standard to US sizing which is the same as Australian sizing. If you're a 10 Australian women's, you will be a 10 US women's.
For half sizes or those between two sizes, we recommend sizing up. Eg: if you are a 9 Australian women's, and you sometimes fit into an Australian women's 8, then we suggest getting a size 9 US. But if you are a large Australian 9 and you sometimes fit into size 10, then we suggest getting a size 10 US.
Demonia women's creepers and ballet flats tend to run small so we also advise sizing up for these. E.g. if you're a 10 in Demonia boots, you would best suit an 11 women's creeper or ballet flat.
Feel free to contact us for individual help with your sizing.