Garments are made in sizes 1, 2 & 3 Basically small, medium and large
Equating approximately to:
Size 1 6-10
Size 2 12-16
Size 3 16-20
The style and fit of the garments are designed to be loose and the width generous to maximise the drape of the fabric and flatter the body.
However, these are guidelines and sizing should allow for personal preference. If you like to wear it even more loose and long, go for the next size up.
If you would like specific measurements don't hesitate to get in touch, I'm always happy to advise. I also provide a made to measure service if you would prefer a more bespoke item.