The Dexcom G7 and G6 both last 10 days per sensor session. The key difference is what happens at the end: the G7 includes a 12-hour grace period after the sensor expires, giving you extra time to replace it without losing glucose data immediately.
Sensor Wear Time: 10 Days for Both
Both the G6 and G7 sensors are approved for 10 days of continuous wear. If you’re switching from the G6 to the G7, your replacement schedule stays roughly the same. The G7’s 12-hour grace period is the practical upgrade here. Once your G7 sensor hits the 10-day mark and notifies you it’s expired, you still get 12 hours to apply a new one. That buffer matters if your sensor expires in the middle of the night or while you’re away from home without a replacement on hand.
The G6 doesn’t offer this grace period. When it expires, it stops, and you’re without CGM data until you insert a new sensor and wait through the warmup.
The G7 15 Day Option
Dexcom also offers a newer version called the G7 15 Day, which extends sensor life to 15 days. This cuts your yearly sensor changes from roughly 36 down to about 24. The tradeoff is a longer warmup: the G7 15 Day requires a 60-minute warmup period before it starts delivering readings, compared to about 30 minutes for the standard G7. The G6 has the longest warmup of the three at approximately 2 hours.
If minimizing the number of sensor changes matters to you, the 15 Day version is worth considering. The sensor itself is the same physical size as the standard G7.
Hardware Differences That Affect Convenience
The G6 uses a separate transmitter that snaps onto each sensor. That transmitter lasts about 3 months before it needs replacing, and you have to remember to pop it off the old sensor and attach it to the new one every 10 days. The G7 eliminated this step entirely. Its transmitter is built into the sensor pod, so the whole unit is disposable. You apply it, wear it, and throw it away.
This integrated design also made the G7 significantly smaller. The G7 sensor measures about 1.07 by 0.94 inches, which is roughly 60% smaller than the G6’s sensor-plus-transmitter combination. The lower profile makes it less noticeable under clothing and less likely to catch on seatbelts, bag straps, or waistbands.
Accuracy Comparison
The G7 has an overall MARD (a standard measure of CGM accuracy, where lower is better) of 8.2% in clinical trials for adults, compared to about 9.0% for the G6. The G7’s 9.5% overall MARD reported in some international datasets still represents strong accuracy. In practical terms, both sensors are highly accurate, but the G7 has a slight edge, particularly in the first 24 hours of wear when CGM readings tend to be least reliable.
Insulin Pump Compatibility
If you use an insulin pump with automated insulin delivery, compatibility may influence which sensor you choose. The G7 now integrates with the Tandem t:slim X2 pump, the Omnipod 5, and the iLet Bionic Pancreas. The G6 was the standard for these systems for years, but pump manufacturers have been updating their software to support the G7. If you’re currently using a G6 with your pump, check whether your specific pump software version supports the G7 before switching.
Cost and Supply Considerations
Because both the standard G7 and G6 use one sensor every 10 days, your monthly sensor cost is similar. The G7 saves you the separate transmitter expense every 3 months since it’s built in. The G7 15 Day version reduces sensor consumption by a third, which can lower out-of-pocket costs if your insurance covers it at the same rate. Your actual savings depend on your plan’s copay structure and whether your pharmacy or supplier stocks the version you want.
For most people upgrading from a G6, the standard G7 feels like the same wear schedule in a smaller, simpler package, with the 12-hour grace period as a genuine quality-of-life improvement on sensor change days.