Here is the size chart for selecting Watery Remington Women's Rashguard. This rashguard is based on chest, hip, bottom line, sleeve length, wrist, and torso measurements to find your correct size.
If you happen to be unlucky and are between two sizes, choose the one that is closest or according to your preferred fit. Additionally, you need to assess which fit you desire; for a tight fit, choose the smaller of the two sizes, conversely, choose the larger of the two sizes if you prefer a looser fit.