Last reviewed August 20, 2026 by the Medically Modern coverage team. Product availability and plan coverage change — confirm with Dexcom and your plan.
Dexcom now sells the G7 sensor in two wear durations. The clinical data and the app experience are broadly similar; what differs is how long each sensor lasts, who it is cleared for, and how many you go through in a month — which is what actually drives your cost.
| Dexcom G7 | Dexcom G7 15 Day | |
|---|---|---|
| Wear time | 10 days | 15 days + 12-hour grace period (15.5 days) |
| Cleared for | Broader age range, including children | Adults 18 and over, all types of diabetes |
| Sensors per 30 days | 3 | 2 |
| Reported accuracy | — | Overall MARD 8.0%, described by Dexcom as its most accurate CGM |
| Prescription | Required | Required |
| Medicare | Dexcom states G6 and G7 are covered | Not listed on Dexcom's Medicare page — confirm before ordering |
The case for the 15-day sensor
- Half the sensor changes. Two insertions a month instead of three. Over a year that is 24 versus 36.
- A built-in grace period. The extra 12 hours means a sensor change that slips past the deadline does not immediately leave you without data.
- Dexcom's stated accuracy figure is strong. An overall MARD of 8.0%, which Dexcom describes as the best across its CGM line.
- Fewer reorder cycles to forget, which in practice is a real cause of supply gaps.
The case for the standard G7
- It is available to children. The 15-day sensor is cleared for adults 18 and over only.
- Coverage is more established. Dexcom lists the G7 as Medicare-covered; the 15-day version is newer and formularies update on their own schedule.
- It is in the assistance program now. Dexcom has indicated the G7 15 Day joins its Patient Assistance Program only a few months after launch.
One honest caveat on the 15 days. In the clearance study, 73.9% of sensors lasted the full 15 days — meaning roughly a quarter did not. That does not make the sensor unreliable, but if you budget on the assumption that every sensor runs the full term, occasional early failures will be an unpleasant surprise. Ask Dexcom about its replacement policy.
Which one does your plan cover?
We check formulary status for the specific product before you order — free, no obligation.
What each costs
Because a month is three standard sensors versus two 15-day sensors, per-sensor prices are misleading. Compare monthly totals. Published cash prices for both land in a similar range — roughly $500–$575 retail per month, and about $180–$320 with a discount card or Dexcom's coupon. Full numbers in the cash price guide.
If you are insured, the comparison that matters is not retail at all but what your plan charges for each product — which can differ if one is on formulary and the other is not. That is the first thing to check.
Where Stelo fits (it does not, really)
Dexcom also sells Stelo, an over-the-counter glucose biosensor that needs no prescription. It is worth naming here only to head off confusion: Stelo is intended for adults 18 and over who do not use insulin (and has also been cleared for children 2 and over who do not use insulin), and it is not indicated for people with problematic hypoglycemia. It is not an alternative to a G7 for anyone dosing insulin.
Frequently asked questions
Should I switch to the 15-day sensor?
If you are an adult, your plan covers it, and fewer sensor changes appeals to you, it is a reasonable switch to raise with your prescriber. Check coverage for the specific product first — a plan covering the standard G7 has not necessarily added the 15-day version.
Do I need a new prescription to switch?
Yes, the prescription specifies the product and quantity, so your prescriber needs to update it. Your supplier or pharmacy can usually initiate that request.
Does the 15 Day sensor use a different app or receiver?
Both work within the Dexcom G7 ecosystem on a compatible smartphone. Confirm current app and receiver compatibility with Dexcom for your specific phone before ordering.
What MARD actually means
Dexcom reports an overall MARD of 8.0% for the G7 15 Day. MARD stands for mean absolute relative difference — on average, how far readings sit from a laboratory reference value, expressed as a percentage. Lower is better. A MARD of 8.0% means readings are typically within about 8% of the reference, so a true glucose of 100 mg/dL might commonly display somewhere in the low-to-mid 90s or high 100s.
Two caveats worth knowing. MARD is an average across a whole study, so individual readings can be further off, particularly when glucose is changing fast. And MARD figures from different manufacturers are not strictly comparable because study designs differ. It is a useful number, not a league table.
Living with each one day to day
| Consideration | Standard G7 | G7 15 Day |
|---|---|---|
| Sensor changes per year | About 36 | About 24 |
| Adhesive time on skin | 10 days per site | 15+ days per site |
| Grace period if you are late changing | — | 12 hours |
| Reorder cycles to remember | More frequent | Fewer |
The adhesive point is the one people underestimate. A sensor that stays on 15 days is 15 days of the same patch of skin under the same adhesive, which suits some people fine and irritates others. If you have had adhesive problems at 10 days, going longer is worth discussing with your clinician before switching — and worth asking about overpatches.
Cost per day, which is the fair comparison
Because the sensors last different lengths of time, comparing sticker prices per sensor tells you nothing. What matters is cost per day of wear, and then cost per month:
- Standard G7: three sensors covers 30 days.
- G7 15 Day: two sensors covers 30 days (31 with the grace periods).
Published cash prices for a month of either land in a broadly similar range — roughly $500–$575 retail, and around $180–$320 with a discount card. So for cash payers the choice is rarely about price. If you are insured, the real question is which product your plan has actually added, because that can produce a much bigger difference than anything intrinsic to the sensors. Numbers are in the cash price guide.
Who should stay on the 10-day sensor
- Anyone under 18. The 15-day sensor is cleared for adults only, so this is not a preference — it is the available option.
- People whose plan covers the G7 but not the 15 Day. A covered sensor beats an uncovered better one.
- Medicare beneficiaries, until coverage is confirmed. Dexcom lists the G6 and G7 as Medicare-covered and does not list the G7 15 Day. See the detail here.
- Anyone who needs the assistance program now. Dexcom has indicated the 15 Day joins its Patient Assistance Program only a few months after launch.
- People with adhesive sensitivity who already struggle to reach day 10.
How to switch if you decide to
Ask your prescriber to write a new prescription naming the G7 15 Day and the quantity — a pharmacy or supplier cannot substitute one product for the other on its own. Before that, have your plan confirm the specific product is covered and what it will cost, because formularies add products on their own schedule. Your existing sensors do not go to waste; finish them and start the new type at your next change.
Sources: Dexcom — G7 15 Day FDA clearance, Dexcom G7 15 Day sensor, Dexcom — G7 15 Day offers FAQ, Dexcom free trial, FDA — OTC CGM clearance.