Dexcom
Dexcom G7
As of August 2026 we track 8 continuous glucose monitors available here, and the cheapest one you can buy without a prescription is the FreeStyle Libre 2 Plus at about £103.98 a month.
Specifications
| Wear time | 10 days |
|---|---|
| Warm-up | 30 minutes |
| Accuracy (MARD) | 8.2% (manufacturer study) |
| Readings | every 5 min |
| Alarms | Yes |
| Prescription | Not required |
What does the accuracy figure mean?
MARD is the average gap between what the sensor says and what a laboratory blood test says, as a percentage. A 10% MARD means readings are off by about 10% on average — so a true 7.0 mmol/L might show as anywhere around 6.3 to 7.7. Lower is better. Most current sensors sit under 10%; twenty years ago they were over 20%. No sensor is exact, which is why treatment decisions still get confirmed with a fingerstick when a reading does not match how you feel.
Pricing
£51.25
to try · 10 days
£1,870.63
per year
- per sensor · 10 days
- £51.25
- per month
- £153.75
excludes VAT
The least you can spend to wear one sensor for its full life. For subscription products it is one month, because you cannot buy less.
Estimated from the sensor price and its wear time, assuming continuous use.
Prices last checked: 2026-08-05
What works well
- Thirty-minute warm-up, the shortest of the medical sensors here
- Strong alarm and follower support, including remote monitoring for a parent or partner
- Works with several automated insulin delivery systems
What to watch out for
- Ten days of wear means more sensor changes than the fifteen-day Abbott sensors, and a higher yearly cost
- An independent head-to-head study measured 13.6% MARD, well above the 8.2% pivotal figure
- UK prices are quoted excluding VAT — you only avoid the 20% if you can claim diabetes VAT relief
Our verdict
The sensor to pick if you want alarms, remote following, or pump integration. The gap between its pivotal accuracy figure and the independent one is the widest of any sensor we list, and worth knowing about.
Read next
- CGM accuracy: what MARD means, and what it hides
MARD is the average gap between a sensor and a laboratory blood test. It is the standard accuracy figure, it is genuinely useful, and it is routinely compared between studies that cannot be compared.
Common questions
- How accurate is the Dexcom G7?
- Dexcom’s pivotal study reported 8.2% MARD for arm placement and 9.1% for the abdomen. An independent head-to-head study of 55 adults reported 13.6%.
- How long does a Dexcom G7 sensor last?
- 10 days, with a grace period after that before the sensor stops reading.