Dexcom G7 vs FreeStyle Libre 3
Dexcom G7 vs Libre 3 comes down to a handful of real differences — wear time, warm-up, cost and what your pump talks to. Here's the comparison, and what happens to your leftover sensors if you do switch.
Head to head
Both are all-in-one sensors worn on the back of the upper arm with no fingerstick calibration and no separate transmitter. Where they differ:
| Feature | Dexcom G7 | FreeStyle Libre 3 |
|---|---|---|
| Maker | Dexcom | Abbott |
| Wear time | 10 days, plus a 12-hour grace period | 14 days (15 on Libre 3 Plus) |
| Warm-up | 30 minutes | About 1 hour |
| Accuracy (MARD, adults) | Around 8.2% | Around 7.9% |
| Sensor size | All-in-one, small | All-in-one, smaller still — among the smallest available |
| Placement (adults) | Back of the upper arm | Back of the upper arm |
| Fingerstick calibration | Not required | Not required |
| Separate transmitter | None — built into each sensor | None — built into each sensor |
| Remote monitoring | Dexcom Follow, up to 10 followers | LibreLinkUp |
| Typical cost | Higher per month without insurance | Generally the cheaper of the two |
These describe the systems as launched, for comparison — not as a substitute for Dexcom's or Abbott's own documentation, and not a recommendation of one over the other. Pump compatibility in particular changes as manufacturers add integrations, so check current specifications with them. Which monitor is right for you is a conversation with your diabetes care team, not a spec sheet.
Nothing carries over between them
These are separate systems from separate manufacturers. G7 sensors don't work with a Libre reader, Libre sensors don't work with the Dexcom app, and there's no transmitter to carry across because both build it into the sensor. Whatever stock you're holding when you switch stays unusable — which is why most people who change systems end up with sealed boxes sitting in a drawer.
Dexcom G7 vs Libre 3: what's the actual difference?
The headline differences are wear time and warm-up. A Libre 3 sensor runs 14 days (15 on Libre 3 Plus) against 10 days plus a 12-hour grace period for the G7, so you change it less often. The G7 warms up in about 30 minutes against roughly an hour for the Libre. Published accuracy is close enough to be a wash for most people — around 7.9% MARD for Libre 3 and 8.2% for G7. Beyond that it comes down to cost, which app and alerts you prefer, and what your pump works with.
Which is more accurate, Dexcom G7 or FreeStyle Libre 3?
On published MARD figures the Libre 3 edges it — roughly 7.9% versus 8.2% — but both sit in a range that's considered strong, and the gap is smaller than the difference between two sensors of the same brand on two different days. Accuracy is rarely the deciding factor between these two. Warm-up, wear time, cost and pump compatibility usually matter more day to day.
Is Libre 3 cheaper than Dexcom G7?
Generally yes, particularly without insurance — Abbott has consistently priced the Libre line below Dexcom. What you actually pay depends far more on your plan, your pharmacy and whatever manufacturer program you qualify for than on list price, so it's worth pricing both through your own coverage rather than going by published figures.
Can I use my Dexcom G7 sensors with a Libre reader, or the other way round?
No. They're entirely separate systems from different manufacturers — different sensors, different apps, different readers. Nothing transfers in either direction. This is why switching between them usually leaves people with unopened boxes that no longer have any use.
What do I do with leftover sensors if I switch?
Sealed, unexpired sensors still in retail packaging hold real resale value — often considerably more per box than test strips. Check the expiration date first: nine or more months of dating is where value peaks, and it falls steadily from there. If the dating is short, a free clinic will usually get more use out of them than you'll get in cash.
Switched already?
We buy both. Dexcom G6 and G7 sensors and FreeStyle Libre 2 and 3 sensors, sealed and in date, from anywhere in the U.S. If you came from a G6 rather than a Libre, the G6 to G7 switch has its own page. And expiration dating drives what any of it is worth.