A blood sugar chart can help people know what range their blood sugar levels should be in at different times of the day.

Doctors use blood sugar charts, or glucose charts, to help people set goals and monitor their diabetes treatment plans. Charts can also help people with diabetes understand their blood sugar levels.

An ideal blood sugar level will depend on individual factors. A doctor will work with each person to establish suitable levels for different times of the day, depending on whether the person has just woken up, eaten, or exercised.

The charts in this article give an idea of suitable blood sugar levels throughout the day. We also explain the importance of staying within the range a doctor advises.

a person using a tool to check for their ideal blood sugar levelsShare on Pinterest
PixelCatchers/Getty Images

Measuring blood glucose levels is an essential step in managing diabetes. Tools for blood glucose management, also called glycemic control, include:

Doctors measure blood sugar levels in milligrams per deciliter (mg/dl), but A1C results may also appear as a percentage. The percentage refers to the amount of hemoglobin that glucose has bound to in the blood.

The following charts outline general target levels for those with and without diabetes.

These figures serve as a guide, but each person’s individual needs vary according to age and other factors. A doctor will work with a person to establish their suitable blood sugar levels and help them stay close to their target goals.

General target levels

General blood sugar target levels are as follows:

Target blood sugar levels for people without diabetesTarget blood sugar levels for people with diabetes
Before meals72–99 mg/dl80–130 mg/dl
2 hours after a mealless than 140 mg/dlless than 180 mg/dl

A1C levels

An A1C test measures a person’s average blood sugar levels over 3 months. It can show if glucose management strategies are working over time.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), a person’s A1C results may be as follows:

A1C level
A person without diabetesbelow 5.7%
A person with prediabetes5.7–6.4%
A person with diabetes6.5% or over

A doctor will need to carry out two tests to diagnose diabetes unless the person shows clear signs of the condition.

Blood sugar charts for children

Ideal blood sugar levels vary at different ages. Based on data from the Nationwide Children’s Hospital, the following chart shows the ideal levels for children aged 0–10 and over.

Blood sugar levels in mg/dl
0–5 years100–180
6–9 years80–140
10 years and over70–120

The following chart, using information from Diabetes UK, gives a rough idea of how a child’s blood sugar levels may vary during the day. However, they do not differentiate by age. A doctor will advise on levels that are suitable to the individual.

Blood sugar levels in mg/dl
On waking72–126
Before meals72–126
2 hours after a meal90–162

Experts note that strict adherence to complex blood sugar targets is not always the best approach, especially for children. Parents may find that a doctor provides more straightforward guidelines for children than adults if the benefits outweigh the risks.

Blood sugar chart for teens

The following are average guideline levels for teens, but people should ask a doctor for individual recommendations.

Blood sugar levels in mg/dl
Before meals72–108
2 hours after a mealup to 180

People with gestational diabetes

Gestational diabetes can occur during pregnancy. Often, it is a temporary condition, but it can lead to pregnancy complications.

The American Diabetes Association (ADA) recommends that people with a diagnosis of gestational diabetes aim for blood sugar levels similar to those for people without diabetes, although individual targets may vary.

The ADA offers the following as a guideline:

Blood sugar level
Before a meal95 mg/dl or less
1 hour after a meal140 mg/dl or less
2 hours after a meal120 mg/dl or less

A doctor will advise the individual on what to do if blood sugar levels are not within the target range.

A doctor may recommend higher blood sugar targets for a person with diabetes than for someone who doesn’t have diabetes.

Target levels vary throughout the day. They tend to be lower before eating and after exercise and higher an hour or so after meals.

When working out a person’s glucose targets, a doctor will consider individual factors, such as:

  • age and life expectancy
  • the presence of other health conditions, particularly cardiovascular disease
  • how long a person has had diabetes
  • problems with the smallest arteries in the body
  • any known damage to the eyes, kidneys, blood vessels, brain, or heart
  • personal habits and lifestyle factors
  • how aware a person is of low blood sugar levels
  • stress

Blood sugar charts often show recommended levels as a range, allowing for differences between individuals.

Why is diabetes more common in Black Americans? Find out here.

Some actions can help adjust glucose levels if they are slightly high or low.

Raising low blood sugar

A person with very low blood sugar, or hypoglycemia, may notice the following symptoms:

  • feeling shaky or jittery
  • being hungry or tired
  • feeling dizzy or lightheaded
  • confusion
  • changes in heart rhythm
  • headache
  • difficulty seeing or speaking

If these symptoms occur, the NIDDK advises people to:

  1. Check their glucose levels.
  2. Consume something containing 15–20 grams of glucose or carbohydrates.
  3. Wait 15 minutes.
  4. Recheck glucose levels.
  5. Repeat if levels are still low.

If levels remain low, the person should seek medical advice. If the individual loses consciousness, someone should seek emergency medical help.

Lowering high blood sugar

High blood sugar is called hyperglycemia and may lead to:

Exercising may help. If high levels persist, the person should speak to a doctor as they may need to adjust their treatment plan.

A person should also contact a doctor if high or low blood sugar symptoms are severe, as they may need emergency medical attention.

What is a diabetic emergency, and what action should a person take?

Monitoring blood sugar levels is an important part of diabetes management. A monitoring plan may include:

  • tests in a doctor’s office
  • a fingerprick test
  • using a CGM device, which monitors glucose levels throughout the day

Typical times a person will check their levels include:

  • before meals
  • before bedtime
  • on noticing symptoms

People may also do additional testing:

  • before, during, and after exercise
  • during the night
  • when unwell
  • after adjustments to their treatment plan

The frequency of testing will vary according to the type and stage of diabetes and individual factors. A doctor will advise the person on how often to test and when.

Usually, the body can manage excess blood sugar either by eliminating it or converting it into fat cells. If high blood sugar levels persist, however, problems can arise.

In time, persistent high blood sugar may result in damage to the:

A wide range of complications can also result, such as slow wound healing and frequent infections. Other possible complications include:

Diabetic ketoacidosis (DKA)

If the body cannot use glucose for energy, it starts to break down fat instead. In doing so, it releases substances called ketones. At high levels, ketones are toxic.

If high levels of ketones build up in the blood, DKA can occur. Symptoms include:

DKA is a life threatening emergency, and a person will need immediate medical attention. Research suggests it is the most common complication of type 1 diabetes.

Why does my breath smell like acetone? Find out more about DKA.

Hyperosmolar hyperglycemic syndrome (HHS)

HHS is a potentially life threatening condition that involves high blood sugar and dehydration.

Symptoms include:

  • extreme thirst
  • increased urination
  • weakness and a feeling of being unwell
  • dry skin
  • changes in vision and consciousness due to reduced blood flow to the brain
  • coma, in severe cases

Anyone showing signs of HHS needs immediate medical attention.

Managing blood sugar levels is an important step in preventing the complications of diabetes. If blood sugar levels stay within a moderate range, this can indicate that treatment is working.

Individual needs can differ, and a doctor will set goals at the start of treatment. They may adjust these targets as treatment progresses.

If anyone has concerns about their blood sugar levels, they should seek medical attention.

Read this article in Spanish.