For everyday tracking, most adults with diabetes use simple targets: before meals, aim for about 4–7 mmol/L, and roughly under 10 mmol/L one to two hours after eating; lab cut‑offs for diagnosing prediabetes and diabetes are stricter (fasting ≥7.0 or 2‑hour ≥11.1 mmol/L for diabetes).
One of the more confusing things about blood sugar is that there are two sets of numbers floating around. The cut-offs your doctor uses to diagnose diabetes are not the same as the targets you'll use day-to-day to manage it. Both are useful — they just answer different questions.
Diagnosis numbers vs. everyday targets
Diagnosis numbers come from a controlled lab setting — a fasting blood draw, or a glucose tolerance test where you drink a measured amount of glucose and they check your level two hours later. They're stricter because they have to cleanly separate "normal" from "prediabetes" from "diabetes".1
Everyday targets are different. They're meant to be checked at home with a finger-prick meter (or a continuous glucose monitor), at moments that match real life — before a meal, an hour or two after a meal, sometimes overnight. They're a little more forgiving because they're tracking how you're doing, not whether you have the condition.2
Diagnosis ranges (lab use)
| Category | Fasting plasma glucose (FPG) | 2‑hour post‑prandial (OGTT / lab) |
|---|---|---|
| Normal | < 5.6 mmol/L | < 7.8 mmol/L |
| Prediabetes | 5.6 – 6.9 mmol/L | 7.8 – 11.0 mmol/L |
| Diabetes | ≥ 7.0 mmol/L | ≥ 11.1 mmol/L |
These cut-offs are the ones the American Diabetes Association uses in its annual Standards of Care, and most other major bodies use the same numbers.1 Diagnosis is not done off a single home meter reading — it's based on lab tests, usually repeated.
Simple everyday targets (for many adults with diabetes)
| Situation | Target (mmol/L) |
|---|---|
| Fasting / before meals | 4 – 7 |
| 1–2 hours after meal start | < 10 |
These are general adult targets — your own doctor may set a tighter or looser range depending on your age, the medications you take, how often you've had hypos (low blood sugar), and other conditions you live with. The point is to give a sane reference frame, not a hard rule.2
When and how often to check
If you take insulin, your team will usually give you a checking schedule. If you don't take insulin, the value of home testing comes from learning what your body does: pick a meal you eat often, check before and again 1–2 hours after, and see what happens. Over a few weeks you'll start to see which meals push you well above 10 mmol/L and which ones don't.3
That's the practical reason the "1–2 hours after the start of the meal" target exists — it's roughly when most people's post-meal glucose peaks. Checking three hours later usually misses the peak.
A practical Hong Kong note
Home glucose meters in Hong Kong report in mmol/L (the same unit used everywhere on this page). Some imported meters or US-based apps default to mg/dL — divide by 18 to convert (so 180 mg/dL ≈ 10 mmol/L). It's worth setting your meter to mmol/L at the start so the numbers match what your doctor talks about.
If you're not sure where to begin, Glukky is a small companion app that handles the above for you.
If you're trying to bring after-meal numbers down, two of the highest-leverage everyday habits are choosing slower carbs (see glycaemic index explained) and the fruit you reach for (see fruit and blood sugar).
