Free Diabetes TrackerWhat the number means
A finger-prick meter measures the amount of glucose (sugar) in your blood. In the UK this is reported in millimoles per litre (mmol/L). The reading goes up after you eat and drifts down between meals and overnight, so the same number can be fine at one time of day and too high at another.
Your target ranges
These are general UK targets from Diabetes UK and NICE. They are a starting point – your own targets are agreed with your diabetes team and may differ, especially if you are older, frail or at risk of hypos.
| Who | Waking / before meals | After meals |
|---|---|---|
| Adults, type 1 | 5 to 7 on waking; 4 to 7 before other meals | 5 to 9 (at least 90 minutes after eating) |
| Children, type 1 | 4 to 7 | 5 to 9 |
| Adults, type 2 | 4 to 7 | Under 8.5 (about 2 hours after eating) |
| In pregnancy | Below 5.3 (fasting) | Below 7.8 at 1 hour, or below 6.4 at 2 hours |
| No diabetes / prediabetes goal | 4.0 to 5.4 | Under 7.8 (about 2 hours after eating) |
NICE does not set a single national blood sugar target for type 2 diabetes, so the type 2 figures are the ones most UK services use – agree yours with your team.
The two numbers that matter most
Whatever your targets, two lines are the same for almost everyone and this app uses them to flag a reading:
- 4 is the floor. Below 4.0 mmol/L is a hypo (low blood sugar) and needs treating straight away.
- 15 and over is very high. At 15 mmol/L or above, especially with type 1, you may need to check for ketones.
When a reading needs action
A single high reading usually isn't an emergency – look for a pattern over a few days. But a hypo, or a very high reading with ketones and feeling unwell, needs acting on now. See what to do about a hypo or a very high reading.
Why log it
One reading is a snapshot. Logging over days and weeks shows the pattern – which times of day run high, how meals and activity change things, and whether a change your team suggested is working. You can start logging free and bring a report to your next appointment.
Checked against NHS and NICE guidance on . See all official sources.