To convert a women's shoe size to men's, subtract 1.5. A women's 9 = men's 7.5. A women's 10 = men's 8.5.
Most sneaker collaborations and limited drops are sized in men's only. Knowing your men's equivalent is essential if you want access to the full release.
Full chart: W6=M4.5, W7=M5.5, W8=M6.5, W9=M7.5, W10=M8.5, W11=M9.5, W12=M10.5.
If a men's size 7 is the smallest available and you wear a women's 9 or larger, you can wear men's. Smaller women's sizes (under 8.5) often need to look for GS (grade school / kids') versions of the same shoe instead.
Test fit matters: men's lasts are slightly wider. Lace tighter or use thicker socks if the fit feels loose.