This is really down to the online retailer to help the customer get the right size jean. Some do and some don't. Denim brands such as 1822 Denim offer a Find My Size tool to use your phone to scan your body to find the best size/ style for you. But not all brands are that forward-thinking so you need to take charge and have your measurements handy when shopping online for jeans. Go to the sizing chart on the website and see if your waist measurement and hip measurement fall into the sizing of their jeans. If your spread over 3 sizes then the brand is not for your shape. However, if you fall into 2 sizes buy both sizes, and send the one back that doesn't fit.