How big is the Sensor?
The Sensor is 5mm in height and 35 mm in diameter.1
Reference
1. FreeStyle Libre flash glucose monitoring system User's Manual.
Do not ignore symptoms that may be due to low or high blood glucose. If you have symptoms that do not match the Sensor glucose reading or suspect that your reading may be inaccurate, check the reading by conducting a finger stick test using a blood glucose meter. If you are experiencing symptoms that are not consistent with your glucose readings, consult your health care professional.