Blood sugar numbers are most useful when you know which test was used, when the reading was taken and whether the number is a diagnostic laboratory result or an individual treatment target.
Quick answer
For nonpregnant adults, a laboratory fasting plasma glucose result is generally considered normal when it is below 6.1 mmol/L (110 mg/dL). A result of 6.1–6.9 mmol/L may indicate prediabetes, while 7.0 mmol/L or higher meets a laboratory diabetes threshold when confirmed appropriately.
On a two-hour 75 g oral glucose tolerance test, below 7.8 mmol/L (140 mg/dL) is normal, 7.8–11.0 mmol/L indicates impaired glucose tolerance and 11.1 mmol/L or higher meets a diabetes threshold.
Quick reference: normal blood sugar ranges in Canada
Canada reports blood glucose in millimoles per litre, or mmol/L. American resources commonly use milligrams per decilitre, or mg/dL.
| Test or timing | Normal or expected | Prediabetes or elevated | Diabetes threshold or common target |
|---|---|---|---|
| Fasting plasma glucose, laboratory test | Below 6.1 mmol/L | 6.1–6.9 mmol/L | 7.0 mmol/L or higher |
| Two-hour 75 g OGTT | Below 7.8 mmol/L | 7.8–11.0 mmol/L | 11.1 mmol/L or higher |
| HbA1c | Below 6.0% | 6.0–6.4% | 6.5% or higher |
| Before meals for many adults with diabetes | Not a diagnostic test | Individual target required | Common target: 4.0–7.0 mmol/L |
| Two hours after meals for many adults with diabetes | Not a diagnostic test | Individual target required | Common target: 5.0–10.0 mmol/L |
Diagnostic ranges are not treatment targets. A standardized laboratory OGTT is also not interchangeable with a home reading after an ordinary meal. Read more about what your blood sugar numbers mean.
What are normal fasting blood sugar levels in Canada?
A fasting plasma glucose test is performed after you have consumed no calories for at least eight hours. Water is usually permitted unless your laboratory gives different instructions.
- Below 6.1 mmol/L: normal fasting laboratory result
- 6.1–6.9 mmol/L: impaired fasting glucose or prediabetes
- 7.0 mmol/L or higher: diabetes threshold
A single unusual home reading does not automatically mean you have diabetes. Illness, stress, poor sleep, dehydration, medication, alcohol, testing technique or food consumed during the fasting period may affect the result.
Is 4.0–6.0 mmol/L a normal fasting range?
A fasting reading of approximately 4.0–6.0 mmol/L is often described as a healthy practical range. The formal Canadian diagnostic boundary is generally stated as below 6.1 mmol/L.
Morning readings can also be affected by hormones, overnight food and medication timing. Learn more about why morning blood sugar may be high.
How are blood sugar levels tested?
Fasting plasma glucose
This test measures glucose after at least eight hours without food. Blood is drawn from a vein and analyzed by a laboratory.
Oral glucose tolerance test
For an OGTT, you fast and then drink a liquid containing 75 grams of glucose. Blood samples are taken before the drink and usually one or two hours afterward.
HbA1c
HbA1c estimates average glucose exposure over roughly the previous two to three months and does not usually require fasting. It can be less reliable in some situations, including certain blood disorders, anemia, recent blood loss, kidney disease and pregnancy.
Home glucose meter
A home meter can help monitor patterns, but it should not be used on its own to diagnose diabetes. Diagnosis requires professional evaluation and appropriate laboratory testing.
What are normal blood sugar levels after meals?
Glucose naturally rises after eating, particularly after meals containing carbohydrates. The size and duration of the rise depend on the meal, physical activity, insulin production, medication, stress, illness, sleep and the exact time the reading is taken.
One hour after eating
Glucose often reaches or approaches its peak around one hour after a meal. Canada does not use one universal one-hour after-meal value to diagnose diabetes in nonpregnant adults. Pregnancy targets are different.
Two hours after eating
For many adults already living with diabetes, a commonly used Canadian treatment target is approximately 5.0–10.0 mmol/L two hours after the beginning of a meal. Individual targets may differ.
A normal two-hour result from a formal 75 g OGTT is below 7.8 mmol/L. An ordinary meal and an OGTT are not interchangeable because the glucose dose is not the same.
What can change a glucose reading?
One number provides limited information. Look for patterns collected under similar conditions.
Common reasons for temporarily higher readings
- Infection, fever, emotional stress or poor sleep
- Steroid medication
- A larger-than-usual carbohydrate portion
- Reduced activity or dehydration
- Testing too soon after eating
- Food residue on the fingers
Common reasons for lower readings
- Too much insulin or glucose-lowering medication
- A skipped or delayed meal
- Alcohol or unplanned exercise
- Vomiting or reduced food intake
- Damaged, expired or improperly stored strips
Wash and dry your hands before testing. If a reading does not match how you feel, repeat the test with a new strip. Read more about how stress affects blood sugar.
When should I call a doctor for high or low blood sugar?
| Situation | Recommended urgency |
|---|---|
| Repeated fasting readings of 7.0 mmol/L or higher without a diagnosis | Arrange a healthcare appointment promptly |
| Repeated after-meal readings above your prescribed target | Contact your diabetes care team |
| Increased thirst, frequent urination, fatigue, blurred vision or unexplained weight loss | Book a medical assessment |
| Repeated glucose below 4.0 mmol/L | Contact your healthcare team |
| High glucose during illness, especially with ketones | Follow your sick-day plan and seek same-day advice |
| Vomiting, abdominal pain, fruity-smelling breath, deep breathing or worsening drowsiness | Seek emergency care |
| Seizure, unconsciousness, severe confusion or inability to swallow | Call 911 immediately |
Do not give food or drink to someone who is unconscious or unable to swallow.
What should you do about borderline results?
A borderline result is a reason to investigate, not a reason to panic.
Record comparable readings
Note the date, time, fasting or meal timing, food, medication, activity, illness, stress, sleep and symptoms.
Build meals around fibre and protein
A practical plate may include half vegetables, one-quarter protein and one-quarter whole grains or another higher-fibre carbohydrate, with water or an unsweetened drink.
Move after meals when appropriate
Light activity after eating may help reduce the size of a post-meal glucose rise. Ask a healthcare professional about exercise if you use insulin, have frequent hypoglycemia, have ketones, have an active foot wound or have been advised to limit activity.
Arrange formal testing
Home readings may reveal a pattern, but a clinician may use fasting laboratory glucose, HbA1c or an OGTT to assess prediabetes or diabetes.
A simple home-monitoring routine to discuss with your clinician
- After waking and before eating.
- Before a selected meal.
- Two hours after the first bite of that meal.
- When symptoms of high or low glucose occur.
- Before driving or exercising when required by your care plan.
Do not begin frequent testing simply because you read this article. The ideal schedule depends on your diagnosis, medication, pregnancy status and reason for testing.
Readers who have been advised to test at home can review the ZenCare blood glucose monitor kit and compatible blood glucose test strips.
Frequently asked questions
What is a normal fasting blood sugar level in Canada?
A normal laboratory fasting plasma glucose result is generally below 6.1 mmol/L. A result of 6.1–6.9 mmol/L may indicate prediabetes, while 7.0 mmol/L or higher meets a diabetes threshold when appropriately confirmed.
Is 6.0 mmol/L fasting blood sugar normal?
A laboratory fasting value of 6.0 mmol/L is below the impaired-fasting-glucose threshold of 6.1 mmol/L, although it should be interpreted with your history and other test results.
Is 7.0 mmol/L high before breakfast?
A laboratory fasting result of 7.0 mmol/L meets a diabetes diagnostic threshold. One home reading is not enough for diagnosis, so arrange professional assessment.
What should blood sugar be two hours after eating?
For many nonpregnant adults already living with diabetes, a common treatment target is 5.0–10.0 mmol/L two hours after the start of a meal. Personal targets may differ.
What is a dangerous low blood sugar level?
For people with diabetes, glucose below 4.0 mmol/L requires prompt action according to their care plan. Unconsciousness, seizures, inability to swallow or severe confusion require 911.
Can I diagnose diabetes with a home glucose meter?
No. A home meter may identify patterns, but diagnosis requires professional evaluation and appropriate laboratory testing.