Blood sugar, or blood glucose, is the amount of sugar circulating in your bloodstream that your cells use for energy. Keeping blood sugar within a healthy range is essential for preventing prediabetes, type 2 diabetes, and long-term complications affecting the heart, kidneys, and nerves. Normal ranges vary depending on when you test, whether you have eaten, and in some cases your age, which is why understanding the full picture is more useful than looking at one number in isolation.
Below is a chart of normal blood sugar levels, followed by what the numbers mean and how to support healthy levels.
Normal Blood Sugar Levels Chart
| Test Type | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| Fasting blood sugar | 70-99 mg/dL | 100-125 mg/dL | 126 mg/dL or higher |
| 2 hours after eating | Under 140 mg/dL | 140-199 mg/dL | 200 mg/dL or higher |
| Random (any time) | Under 140 mg/dL | 140-199 mg/dL | 200 mg/dL or higher (with symptoms) |
| HbA1c (3-month average) | Below 5.7% | 5.7%-6.4% | 6.5% or higher |
Note: These ranges apply to most non-pregnant adults. Older adults, children, and pregnant women may have different target ranges set by their doctor.
Understanding Fasting Blood Sugar
Fasting blood sugar is measured after at least eight hours without eating, typically first thing in the morning. It reflects how well your body regulates glucose overnight and is one of the most common screening tests for diabetes and prediabetes.
Understanding Post-Meal (Postprandial) Blood Sugar
Blood sugar naturally rises after eating as food is digested and glucose enters the bloodstream. A healthy body brings this level back down within a couple of hours. Levels that stay elevated longer can be an early sign of insulin resistance.
Understanding HbA1c
The HbA1c test measures your average blood sugar over the past two to three months by looking at how much sugar has attached to your red blood cells. Because it reflects a longer time frame, it is considered one of the most reliable tools for diagnosing and monitoring diabetes.
If you’ve had an A1C test specifically, this normal A1C levels chart breaks down what that specific result means in more detail. And pairing high readings with dietary changes, like the ones in our guide to foods that help lower blood sugar spikes after meals, can help bring post-meal numbers down.
How Blood Sugar Targets Can Shift with Age
While the standard diagnostic ranges above apply broadly across adulthood, doctors often set slightly higher target ranges for older adults, particularly those with multiple health conditions, to reduce the risk of dangerously low blood sugar (hypoglycemia). Children and pregnant women also have their own distinct target ranges that a doctor should establish individually.
Signs Your Blood Sugar May Be Too High
- Increased thirst and frequent urination
- Fatigue and difficulty concentrating
- Blurred vision
- Slow-healing cuts or wounds
- Unexplained weight loss
How to Support Healthy Blood Sugar Naturally
- Choose fiber-rich carbohydrates like whole grains, legumes, and vegetables over refined sugar
- Pair carbohydrates with protein or healthy fat to slow glucose absorption
- Stay physically active, since exercise helps muscles use glucose more efficiently
- Maintain a healthy weight, particularly around the midsection
- Prioritize consistent sleep, since poor sleep is linked to insulin resistance
- Manage stress, as chronic stress hormones can raise blood sugar
When to See a Doctor
If your fasting or random blood sugar readings fall into the prediabetes or diabetes range, or if you notice symptoms like excessive thirst, frequent urination, or unexplained fatigue, it is important to follow up with your doctor. Early intervention with diet, exercise, and sometimes medication can prevent prediabetes from progressing to type 2 diabetes.
The Bottom Line
Understanding where your blood sugar falls, whether fasting, after meals, or as a long-term average, gives you a clearer picture of your metabolic health than any single test alone. Combining regular screening with a balanced diet, movement, and healthy sleep habits is the most effective way to keep blood sugar in a healthy range.
This article is for informational purposes only and is not a substitute for professional medical advice. Please consult your healthcare provider to interpret your specific test results and determine an appropriate monitoring plan.
