Looking a buy some women's clothing I'm a 34 waist any idea on convert that to a female size? 12, 14 etc
Honestly it varies with each brand. Most items have a size guide with waist measurements, so might be worth looking for some items you like and checking out the guide.
i'm a 32 waist and usually get 10/12s that fit, Id probaby recommend 14 or even a 16, but as NatandTom says, it varies quite widely from brand to brand.