All you need to do is follow this post :)
1. Let’s start with the obvious; you want to measure yourself without cloths on. Don’t worry, you don’t have to take it all off, but it is recommended that you measure yourself with tights and a top or any other combination works for you, in order to get the most accurate measurements.
2. Measuring tape. If you don’t have a measuring tape, use any cord or ribbon and a ruler.
3. Where to measure?
* Bust: Measure under your arms at your chest’s fullest point.