According to Dexcom, a Dexcom G7 sensor lasts up to 10 days plus a 12-hour grace period, and a Dexcom G7 15 Day sensor lasts up to 15 days plus a 12-hour grace period. A Dexcom G6 sensor lasts up to 10 days, and its separate G6 transmitter has a battery that lasts 3 months.

Dexcom wear times at a glance

Dexcom G6: a 10-day sensor and a 3-month transmitter

The Dexcom G6 has two parts that run on different clocks. Dexcom says “A single Dexcom G6 sensor can be worn up to 10 days” (Dexcom). The transmitter clips into each new sensor, and Dexcom says “The transmitter battery is good for 3 months” (Dexcom). That works out at roughly nine sensors per transmitter.

When does the G6 transmitter battery run out?

You’ll get a warning well before it does. Per Dexcom:

Dexcom recommends having your next transmitter in hand within 3 months of starting the current one, so order early.

Dexcom G7: up to 10 days plus a 12-hour grace period

Dexcom says: “The Dexcom G7 sensor is indicated to be worn for up to 10 days, with a 12-hour grace period at the end” (Dexcom). The grace period gives you up to 10.5 days in total, so you have time to change the sensor at a convenient moment rather than the minute it ends.

How long does the Dexcom G7 transmitter last?

There’s no separate transmitter to keep track of. In Dexcom’s words, “Dexcom G7 features an all-in-one sensor and transmitter” (Dexcom). The transmitter is built in, lasts as long as the sensor, and is replaced along with it. Comparing the two systems? See our Dexcom G7 vs G6 review.

Dexcom G7 15 Day: up to 15.5 days, adults 18 and over

The Dexcom G7 15 Day is “indicated for 15 days of wear” with “an additional 12-hour grace period”, which makes 15.5 days in total (Dexcom). Like the G7, the transmitter is built into the sensor. Dexcom says the G7 15 Day is for adults aged 18 and over, while the standard G7 is for ages 2 and older (Dexcom).

Dexcom is upfront that not every sensor makes it to day 15. In its own study, “73.9% of sensors lasted the full 15 days”. Dexcom adds that when used as labelled, “approximately 26% of sensors may not last for the full 15 days” (Dexcom). So if yours ends early, you’re not alone, and there’s a process for it (see below).

Is the Dexcom G6 discontinued?

Yes, in the US. Dexcom says: “Starting July 1, 2026 Dexcom G6 will no longer be manufactured”, and that it “will not be able to guarantee availability or inventory for Dexcom G6 beyond this date” (Dexcom). Dexcom is moving people to the Dexcom G7 or Dexcom G7 15 Day. If you still use a G6, speak to your care team or supplier about switching before your stock runs out.

Two clocks: the sensor and the patch

If you wear an overpatch, there are two separate clocks running, and it helps to keep them apart:

A patch never makes a sensor run past Dexcom’s wear time. When the sensor session ends, it ends, however well the patch is holding. What a patch does is help the sensor reach the end of its session in the first place. Our guide to how long a CGM patch should last covers the patch clock in more detail.

When a Dexcom sensor ends early

Sensors end early for two broad reasons, and they need different fixes.

A sensor fault. Sometimes a sensor simply stops working. Dexcom says that if a sensor fails before the end of its expected life, “the user must contact Dexcom Tech Support as soon as possible”. Dexcom reviews each case, and if the sensor didn’t meet its published performance, “a replacement sensor will be issued, with no limit, at no cost to the patient” (Dexcom). A patch can’t fix a fault like this.

A sensor knocked or peeled off. This is the one a patch helps prevent. Once a sensor comes off, it’s usually finished, because the filament under your skin comes out with it. Doorframes, towels, seatbelts, sport and sweat all play a part. An overpatch sits over the sensor and holds its edges down, so there’s less for anything to catch.

Wondering if your G7 needs one? Read Dexcom G7 overpatches: what they are and why you might need one. For skin prep and other ways to keep a sensor on, see how to extend the life of your Dexcom sensor.

FAQ

How many days does a Dexcom sensor last?

It depends on the system. Dexcom says a Dexcom G6 sensor lasts up to 10 days, a Dexcom G7 sensor up to 10 days plus a 12-hour grace period, and a Dexcom G7 15 Day sensor up to 15 days plus a 12-hour grace period.

When does my Dexcom sensor expire?

Your sensor session ends when its wear time is up: after 10 days for a G6, after 10.5 days (including the grace period) for a G7, or after 15.5 days for a G7 15 Day. Unused sensors also have a use-by date printed on the packaging, so check it before you apply one.

Is the Dexcom G6 discontinued?

Yes. Dexcom says the G6 will no longer be manufactured from 1 July 2026 and it can’t guarantee G6 supply after that date. Dexcom is moving users to the G7 or G7 15 Day.

How often does a CGM need to be replaced?

For Dexcom, every 10 days for the G6 and G7, or every 15 days for the G7 15 Day. G7 sensors have a 12-hour grace period to make the change easier. The G6 transmitter is replaced separately, every 3 months.