It’s usually US sites that quote square inches. I think it’s better to go with dimensions because something long and very narrow can have the same number of square inches as something square (and something square is much better for use of floor area). So 80cm by 50cm (or in the US in inches it’s about 32” x 20” but check my maths!) is usually considered the minimum size for a Syrian. Eg Hamster Heaven size. The old Rspca minimum used to be 75 x 45 cm. There aren’t many cages that size. Most animal charities say 80 x 50. Bigger than that is usually better for a Syrian for more enrichment but it depends on the hamster. And how much out of cage time they get. It’s easier to set up a 100cm cage for a Syrian I think as some of their stuff is bigger. I had both our Syrians in 100 x 50 cages but they both had very big labyrinth houses - which wouldn’t fit in a smaller cage. Currently our Syrian is in an 80 x 50 cage snd has a good sized long house at one end. There is no way a labyrinth house would fit in there and leave enough floor space. He seems to prefer that cage and is out more in it. Our last Syrian was happy as Larry in his 100 cm cage. For some Syrians no cage is big enough!
Some people would say if it’s not at least 50 cm (20”) deep it’s not suitable. But I think that is a bit jobsworth when you have a nice big detolf with loads of scope for enrichment
. There’s a lot of drama and rubbish on the internet sometimes
. A detolf is a palace!
In terms of US minimums I think it used to be 360 square inches then got put up to 450 (which I think is equivalent to 75cm x 45cm - eg a duna multy. People talk about recommended minimums but the aspca in the US only had a minimum of a 20 gallon tank - which I think most people would agree is far too small.
In Germany they have a welfare minimum of 100cm x 50cm and a recommended minimum of 1 metre square - but those are all tank set ups or diy cages usually. There is a lot of discussion on this topic as hamsters need human interaction as well as nice environments. Maybe they’d be fine without human interaction in a huge habitat with lots of enrichment but then it comes down to - is this a pet or just trying to recreate an ideal habitat as if they weren’t a pet. Sorry it’s late - I am not being very coherent there!