FAQ: How long does it take for my CGM to calibrate?


How long does it take for my CGM to calibrate?


Your sensor might take up to 48 hours to calibrate, and will typically become more accurate the longer you wear it. In the beginning, it’s better to pay attention to your glucose spikes and valleys instead of the absolute numbers. Accuracy can be improved with a finger stick calibration with the Dexcom sensors, but this isn't required - it’s also important to understand that finger stick readings will never exactly match the sensor reading. 

Pro tip: One thing we've found that can greatly impact calibration is paying attention to when the CGM is applied. We recommend applying the CGM in the morning, in a fasted state and avoiding eating or intense exercise during the warm-up period. 

Dr. Casey Means on Calibration

Further Reading:

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