Blood Sugar Level Ranges

Understanding blood glucose level ranges is key to both diabetes diagnosis and diabetes self-management.

This page states 'normal' blood sugar ranges and blood sugar ranges for adults and children with type 1 diabetes, type 2 diabetes and blood sugar ranges to determine people with diabetes.

If a person with diabetes has a meter, test strips and is testing, it's important to know what the blood glucose level means.

Recommended blood glucose levels have a degree of interpretation for every individual and you should discuss this with your healthcare team.

In addition, women may be set target blood sugar levels during pregnancy.

The following ranges are guidelines provided by the National Institute for Clinical Excellence (NICE) but each individual’s target range should be agreed by their doctor or diabetic consultant.

Recommended target blood glucose level ranges

The NICE recommended target blood glucose levels are stated below alongside the International Diabetes Federation's target ranges for people without diabetes.
NICE recommended target blood glucose level ranges

Target Levels
by Type
Before meals
(pre prandial)
2 hours after meals
(post prandial)
Non-diabetic 4.0 to 5.9 mmol/L under 7.8 mmol/L
Type 2 diabetes 4 to 7 mmol/L under 8.5 mmol/L
Type 1 diabetes 4 to 7 mmol/L under 9 mmol/L
Children w/ type 1 diabetes 4 to 8 mmol/L under 10 mmol/L

NB: There are differening opinions about the ideal blood glucose level range. You should discuss your own individual needs with your healthcare team.

For people with diabetes, blood sugar level targets are as follows:

  • Before meals: 4 to 7 mmol/L for people with type 1 or type 2 diabetes
  • After meals: under 9 mmol/L for people with type 1 and 8.5mmol/L for people with type 2

As is visible from the NICE targets, children with type 1 diabetes have a greater upper limit for their blood sugar levels by 1mmol/L.

How are blood sugar level ranges used to diagnose diabetes?

There are 2 main tests which are conducted to determine whether someone has diabetes.

Impaired fasting glycemia test

When being tested for diabetes by a impaired fasting glycemia test, blood sugar levels will normally be taken after around eight hours of fasting.

During this blood sugar levels are put into the following categories:

  • Normal: 4.0 to 5.9 mmol/l (70 to 107 mg/dl)
  • Prediabetes or Impaired Glucose Glycemia: 6.0 to 6.9 mmol/l (108 to 126 mg/dl)
  • Diagnosis of diabetes: more than 6.9 mmol/l (126 mg/dl)

Impaired glucose tolerance test

An impaired glucose tolerance test involves taking a concentrated amount of glucose and then measuring blood sugar levels after two hours.

Impaired glucose tolerance or diabetes is diagnosed as follows:

  • Normal: under 7.8 mmol/l (140 mg/dl)
  • Prediabetes or Impaired Glucose Tolerance: 7.9 to 11.1 mmol/l (141 to 200 mg/dl)
  • Diagnosis of diabetes: more than 11.1 mmol/l (200 mg/dl)