Here's a handy size guide and a couple of tips to help you find the perfect fit
To measure your waist, measure around the slimmest part of your natural waistline, or just below if that is where you prefer your waistband to sit
To measure your hips, measure around the fullest part of your hips and bottom
The inseam measurement measures the inside seam length from the lowest part of the crotch to the bottom of the hem. Measure this seam on some of your favourite trousers and this should give you a good idea of what length you prefer
If you're not sure what size is right for you because your measurements fall in between sizes, go for the size down.