Normal blood sugar levels in Australia: chart and ranges

Normal blood sugar levels in Australia sit between 4.0 and 7.8 mmol/L across the day for adults without diabetes. A fasting result below 6.1 mmol/L is normal, 6.1 to 6.9 mmol/L is impaired fasting glucose (prediabetes), and 7.0 mmol/L or above is in the diabetes range. For HbA1c, 6.5% or above is the diabetes cut-off.

If you have a result in front of you, type it in below. Choose fasting, HbA1c, any time of day or 2 hours after eating, and the checker shows where it sits against Australian ranges.

Normal blood sugar levels chart for Australia

This chart puts the Australian ranges for each test in one place. All glucose figures are in mmol/L.

Charts from overseas can look different for two reasons. US sites use mg/dL (multiply mmol/L by 18). US guidelines also start prediabetes at a fasting 5.6 mmol/L (100 mg/dL), while Australian doctors use 6.1 mmol/L.

Normal fasting blood sugar

A normal fasting blood sugar in Australia is below 6.1 mmol/L, and most lab reports print a reference range of about 3.4 to 5.4 mmol/L.

Fasting means nothing to eat or drink except water for at least 8 hours, usually overnight. A fasting glucose test is the most common way blood sugar is checked.

The two numbers do different jobs. The lab range describes where most healthy people sit. The 6.1 cut-off is the line Australian doctors use for diagnosis. A result in between is not prediabetes, but Australian GP guidance treats 5.5 to 6.9 mmol/L as a reason to test further, usually with an HbA1c or an oral glucose tolerance test.

Blood sugar across the day and after meals

Without diabetes, blood sugar generally stays between 4.0 and 7.8 mmol/L all day, including after meals.

It rises after you eat and is usually back under 7.8 mmol/L within 2 hours of starting a meal. A brief rise above 7.8 after a large carbohydrate meal can happen in healthy people. We cover the 1 and 2 hour picture, with example readings, in what your blood sugar should be after eating.

The formal after-meal test is the oral glucose tolerance test (OGTT): a measured glucose drink after an overnight fast, with blood taken 2 hours later. Under 7.8 mmol/L is normal, 7.8 to 11.0 is impaired glucose tolerance, and 11.1 or above is in the diabetes range.

HbA1c: your two to three month average

HbA1c measures how much glucose has attached to your red blood cells, which gives an average of your blood sugar over the last two to three months.

Australian reports print HbA1c in % and in mmol/mol. Our HbA1c calculator converts between the two and shows the average blood sugar your result reflects.

The typical lab reference range is 4.0 to 5.9% (20 to 41 mmol/mol). Vively's optimal range is 4.0 to 5.3% (20 to 34 mmol/mol), so we can flag a drift earlier. An HbA1c of 6.0 to 6.4% (42 to 46 mmol/mol) is in the prediabetes range. An HbA1c of 6.5% (48 mmol/mol) or above is the cut-off Australian doctors use for diabetes, and they confirm it with a repeat test.

Because it is an average, HbA1c can look fine while daily swings are large. Anything that shortens red blood cell life, such as some anaemias or recent blood loss, can make it read falsely low. Read more about the HbA1c test.

Normal blood sugar levels by age

Australian adult blood sugar ranges do not change with age: the same cut-offs apply at 25 and at 75.

Charts that list a different normal range for every decade do not come from Australian guidelines. Glucose does drift up slightly with age, though. In a 2019 CGM study of 153 healthy people aged 7 to 80, led by Viral Shah, average glucose was 5.4 to 5.5 mmol/L in most age groups and 5.8 mmol/L in people over 60, still well inside the usual range.

Diabetes risk rises with age too, which is why regular checks matter more as you get older.

HbA1c drifts up gently with age too. Our guide to HbA1c levels by age shows typical results for women and men from 6,085 Vively members.

Our members' CGM data shows the same gentle drift after meals. Among 4,871 Vively CGM members without diabetes, the typical reading 2 hours after eating was 5.6 mmol/L in their 20s and 5.8 mmol/L at 60 and over, well under 7.8.

To see where your own reading sits, try our after-meal reading checker. It shows the Australian guideline for your number and compares it with members your age.

Children

Children's targets, including for type 1 diabetes, are set by their diabetes care team. We do not list them here, because they depend on the child and their treatment.

Pregnancy

Pregnancy uses its own targets and a specific glucose tolerance test. See our gestational diabetes blood sugar chart for those.

Older adults with diabetes

For older people with diabetes, especially those with other health conditions or a risk of falls, doctors may set less tight targets to avoid lows. Your GP or specialist decides these with you.

Blood sugar targets for type 1 and type 2 diabetes

Diabetes Australia's general targets are 4.0 to 7.0 mmol/L before meals and 5.0 to 10.0 mmol/L two hours after starting a meal.

These are starting points. Your GP or specialist may set different targets depending on your age, your medicines, your risk of hypos and your other health conditions.

Test strips are subsidised through the NDSS for registered people with diabetes who use insulin, and for people with type 2 diabetes not using insulin who have been advised to monitor by a health professional (initial six-month supply). Our guide to CGMs in Australia compares FreeStyle Libre, Dexcom and Sibionics.

What level of blood sugar is dangerous?

Both very low and very high blood sugar can be dangerous, and the symptoms matter as much as the number.

Low blood sugar (hypoglycaemia)

Diabetes Australia's targets start at 4.0 mmol/L, and for people with diabetes a reading below that is treated as a hypo. Lows mostly affect people using insulin or some diabetes tablets.

• Early signs: shakiness, sweating, hunger, dizziness, a racing heart, irritability.
• Severe signs: confusion, slurred speech, drowsiness, seizures or passing out.
• What to do: have fast-acting carbohydrate straight away, such as jelly beans, glucose tablets, or regular (not diet) soft drink or juice. Recheck, repeat if still low, then eat something with longer-acting carbohydrate.
• Emergency: if someone is drowsy, cannot swallow safely or is unconscious, do not give food or drink. Call 000.

Without diabetes, true lows are uncommon. Feeling shaky a few hours after a sugary meal can be reactive hypoglycaemia, and CGM wearers often see false lows overnight from lying on the sensor (more on low readings at night).

High blood sugar (hyperglycaemia)

Signs of high blood sugar include thirst, passing more urine, tiredness, blurred vision, headaches and cuts that are slow to heal.

• 11.1 mmol/L or more with symptoms: see a GP promptly, whether or not you have diabetes.
• Very high and unwell: a very high reading with vomiting, drowsiness, deep or fast breathing, stomach pain or confusion needs urgent care. Call 000 or go to an emergency department. These can be signs of diabetic ketoacidosis or a hyperosmolar state, both medical emergencies.

What high blood glucose can mean

An occasional high after a big meal is normal, while highs that keep happening can mean your body is handling glucose less well.

Common reasons for a high reading:

• Food: a large serve of fast-digesting carbohydrate or sugary drinks.
• Illness and stress: infections and stress hormones such as cortisol push glucose up.
• Poor sleep: a short night can make insulin work less well the next day.
• Medicines: steroids such as prednisolone can raise glucose.
• The dawn effect: an early-morning rise in hormones that lifts glucose before breakfast.

Some people are more likely to run high: those with a family history of type 2 diabetes, extra weight around the waist, an inactive lifestyle, older age, or past gestational diabetes or PCOS. Risk is also higher for Aboriginal and Torres Strait Islander people, and people of South Asian, Chinese or Pacific Islander background. Most people with prediabetes have no symptoms, so testing is how it is found (see the signs of prediabetes).

When glucose is normal but insulin is not

Your blood sugar can stay normal for years while your body makes more and more insulin to hold it there.

This is insulin resistance, and fasting glucose and HbA1c are late to show it. A fasting insulin test can show the extra work earlier. The reference range is 3 to 10 mIU/L, and our optimal range is 3 to 5 mIU/L.

HOMA-IR combines fasting glucose and fasting insulin into one score. Vively's optimal HOMA-IR is 1.0 or below. It is not printed on most lab reports.

You can work out your own score with our HOMA-IR calculator.

In this example, fasting glucose (5.1 mmol/L) and HbA1c (5.4%) are both in range. Fasting insulin (9 mIU/L) is inside the lab range but above our optimal, and HOMA-IR (2.0) is above our optimal of 1.0, which is the early pattern worth catching. We explain why in fasting insulin as an early test.

How to measure your blood sugar

Lab tests diagnose, and home devices help you track.

• Lab blood tests: fasting glucose, HbA1c and the OGTT are done at a pathology collection centre. Every pathology test in Australia needs a doctor to sign the request.
• Finger-prick meter: one drop of blood gives a reading in seconds. Useful for checking specific moments, such as before breakfast or 2 hours after a meal.
• Continuous glucose monitor (CGM): a small sensor on the arm reads glucose in the fluid under the skin every few minutes, for 10 to 15 days depending on the sensor.

How Vively can help

The Vively Baseline Health Check includes 70+ biomarkers in the $99 a month membership. A GP from our network signs your request after a short telehealth consult, so you do not need to visit your own GP first. The Baseline lab tests can be Medicare-rebated; your membership pays for the analysis, your report, the app and your practitioner. Blood collection is available through 3,700+ collection centres, with results usually within a few days.

Frequently asked questions

Do normal blood sugar levels change with age?

No. Australian adult cut-offs are the same at every age: 4.0 to 7.8 mmol/L across the day, and a fasting result below 6.1 mmol/L. Average glucose drifts up a little after 60 but stays in the usual range. Targets for children, for pregnancy and for older people with diabetes are set individually by their care team.

What blood sugar level is dangerous?

Both lows and highs can be. For people with diabetes, a reading below 4.0 mmol/L is treated as a hypo and needs fast-acting carbohydrate. A reading of 11.1 mmol/L or more with thirst or frequent urination needs a GP promptly. Very high readings with vomiting, drowsiness, deep breathing or confusion need urgent care, so call 000.

What are normal blood sugar levels for type 2 diabetes in Australia?

Diabetes Australia's general targets are 4.0 to 7.0 mmol/L before meals and 5.0 to 10.0 mmol/L two hours after starting a meal. These apply to type 1 and type 2 diabetes as starting points. Your GP or specialist may set different targets depending on your age, medicines, risk of hypos and other health conditions.

What is the normal BGL range?

BGL stands for blood glucose level. For adults without diabetes in Australia, a normal BGL is 4.0 to 7.8 mmol/L across the day. A fasting BGL below 6.1 mmol/L is normal, and most lab reports show a fasting reference range of 3.4 to 5.4 mmol/L.

Why do US blood sugar charts show different numbers?

They use different units and a different prediabetes cut-off. The US uses mg/dL, so 7.8 mmol/L appears as 140 mg/dL (multiply by 18). US guidelines also start prediabetes at a fasting 5.6 mmol/L (100 mg/dL), while Australian doctors use 6.1 mmol/L and treat 5.5 to 6.9 mmol/L as a reason for further tests.

Sources

1. Diabetes Australia. Blood glucose levels and targets.
2. Diabetes Australia. Pre-diabetes.
3. Diabetes Australia. Hyperglycaemia.
4. Royal Australian College of General Practitioners. Oral glucose tolerance testing. Australian Family Physician, 2012.
5. Royal College of Pathologists of Australasia. RCPA Manual: Glucose.
6. Shah VN, et al. Continuous glucose monitoring profiles in healthy nondiabetic participants: a multicenter prospective study. J Clin Endocrinol Metab. 2019;104(10):4356-4364.
7. National Diabetes Services Scheme. Blood glucose monitoring strips.