# Normal blood sugar levels: what's healthy, what's too low and what's dangerous

A number on a meter or a lab report means little until you know what it’s being compared with. Here are the ranges the CDC, the American Diabetes Association and the NHS use, and what to do when yours is outside them.

Source: https://nourishandstrong.com/normal-blood-sugar-levels
Published: 2026-11-08
Updated: 2026-11-08
By: the Nourish & Strong team
General information, not medical advice.

**The short answer:** for an adult without diabetes, a normal fasting blood sugar is 99 mg/dL (5.5 mmol/L) or below, and a normal A1C is below 5.7%. Below 70 mg/dL (3.9 mmol/L) is low. For most people with diabetes, the American Diabetes Association suggests 80 to 130 mg/dL before meals and under 180 mg/dL at the peak after eating.

Blood sugar, or glucose, rises after you eat and falls between meals. A single reading is a snapshot. What it means depends on when you took it and whether you have diabetes. If you’re still wondering whether you have diabetes at all, start with our guide to [diabetes symptoms](https://nourishandstrong.com/diabetes-symptoms).

## What are normal blood sugar levels?

Normal blood sugar levels depend on the test. The CDC gives these ranges for adults, and the American Diabetes Association goals for people with diabetes sit in the last column:

| Test | Normal | Prediabetes | Diabetes | Common goal if you have diabetes |
| --- | --- | --- | --- | --- |
| Fasting (8+ hours, water only) | 99 mg/dL (5.5 mmol/L) or below | 100 to 125 mg/dL (5.6 to 6.9) | 126 mg/dL (7.0) or above | 80 to 130 mg/dL before meals |
| 2 hours into a glucose tolerance test | Below 140 mg/dL (7.8) | 140 to 199 mg/dL (7.8 to 11.0) | 200 mg/dL (11.1) or above | Under 180 mg/dL at the peak after a meal |
| Random test, any time of day | Not used | Not used | 200 mg/dL (11.1) or above | Not used |
| A1C (3-month average) | Below 5.7% | 5.7% to 6.4% | 6.5% or above | Under 7% for many adults |

Sources for the table: the CDC and the American Diabetes Association Standards of Care. A doctor usually repeats a test on a second day before diagnosing diabetes, the ADA says. If a pharmacy or health fair test came back high, the CDC suggests seeing your doctor to be re-tested. The A1C works differently from a meter reading, and our guide to [A1C vs blood sugar](https://nourishandstrong.com/a1c-vs-blood-sugar) explains how the two line up.

## What is normal blood sugar in the morning?

Normal blood sugar in the morning, before you eat, is 99 mg/dL or below if you don’t have diabetes. That first reading of the day is effectively a fasting test, since the ADA defines fasting as at least 8 hours with nothing but water. If you have diabetes, the ADA’s usual goal before meals is 80 to 130 mg/dL (4.4 to 7.2 mmol/L).

The NHS uses a similar line for people with diabetes: a home reading over 7 mmol/L (about 126 mg/dL) on waking or before eating counts as high.

## Is blood sugar higher in the morning?

Blood sugar can be higher in the morning, even before you’ve eaten. The ADA calls this the dawn phenomenon: a surge of hormones the body makes every day around 4 to 5 a.m. In people with diabetes, it can push the waking reading up. The ADA also lists illness, such as a cold or flu, and other stress as reasons a reading can run high. If your morning numbers keep creeping up, write them down and show them to your care team.

## What is normal blood sugar after eating?

Blood sugar after eating should come back below 140 mg/dL within about 2 hours if you don’t have diabetes. That’s the CDC’s normal cutoff for the 2-hour glucose tolerance test, where you drink a sugary drink and have your blood checked. If you have diabetes, the ADA’s usual goal is a peak under 180 mg/dL (10.0 mmol/L) after a meal. The NHS counts a home reading over 11 mmol/L (about 200 mg/dL), taken at least 90 minutes after eating, as high.

What’s on the plate shapes that curve. A breakfast with protein and fiber, like the ones in our [high-protein breakfast ideas](https://nourishandstrong.com/high-protein-breakfast-ideas), is a sensible place to start. Our list of [high-fiber foods](https://nourishandstrong.com/high-fiber-foods) makes it easy to add some to every meal.

## What blood sugar level is too low?

Blood sugar below 70 mg/dL (3.9 mmol/L) is too low, and below 54 mg/dL (3.0 mmol/L) is severe, according to the CDC. The ADA sorts lows into three levels:

| Level | Reading | What it means |
| --- | --- | --- |
| Level 1 | 54 to 69 mg/dL (3.0 to 3.8 mmol/L) | Low. Treat it now. |
| Level 2 | Below 54 mg/dL (3.0 mmol/L) | Severe low. Treat it right away. |
| Level 3 | Any reading | Severe: the person is confused or can’t treat themselves and needs help from someone else. |

Early signs include a fast heartbeat, shaking, sweating, nervousness, irritability or confusion, dizziness and hunger, the CDC says. The NHS adds tingling lips and blurred vision. Some people don’t feel any warning signs, which the ADA calls hypoglycemia unawareness.

**How to treat a low (the ADA’s 15-15 rule):**

- At 70 mg/dL or below, have 15 grams of fast-acting carbs. That’s half a cup (4 oz) of juice or regular soda, 1 tablespoon of sugar or honey, or glucose tablets (check the label, as each has about 4 to 5 grams).
- Check again after 15 minutes. If you’re still below 70, have another 15 grams.
- Once you’re back above 70, eat a snack with protein and carbs if your next meal isn’t soon.
- Skip chocolate and peanut butter for this. The ADA says they’re poor choices for treating a low.
- If you think you’re low and can’t check, treat it anyway.

## What blood sugar is too low for a non-diabetic?

For someone without diabetes, there’s no single cutoff. Cleveland Clinic says readings between 50 and 70 mg/dL (2.8 to 3.9 mmol/L) can be normal, and that one low reading usually isn’t a concern. The NHS says lows are rare in people without diabetes. If you keep getting symptoms of a low, see your doctor. Cleveland Clinic lists liver or kidney disease, an underactive thyroid, Addison’s disease, heavy drinking and, rarely, a tumor called an insulinoma as possible causes. Shakiness and fatigue have many other causes too, which our guide to [why you’re always tired](https://nourishandstrong.com/why-am-i-always-tired) walks through.

## What blood sugar level is dangerous?

Blood sugar becomes dangerous when it’s low enough to cause confusion or passing out, or high enough to come with ketones or feeling very unwell. On the low side, below 54 mg/dL is severe. On the high side, there’s no single number. The warning signs and ketones matter more.

The ADA says to check your urine for ketones when your blood sugar is above 240 mg/dL, and not to exercise if ketones are present. A blood ketone level of 1.6 mmol/L or higher needs emergency care right away, because it can mean diabetic ketoacidosis (DKA), which can develop quickly.

**Call 911, your local emergency number, or go to the ER if:**

- Someone is confused, passing out, having a seizure or can’t swallow. Give glucagon if they have it and you know how. Call 911 if there’s no glucagon.
- They haven’t recovered 10 minutes after glucagon, or a low comes after drinking alcohol.
- High blood sugar comes with vomiting or stomach pain, fast breathing or a fast heartbeat, drowsiness, fruity-smelling breath, confusion or high ketones.

Never give food or drink to someone who’s unconscious. Put them in the recovery position. Don’t drive yourself to the hospital. These steps come from the NHS and the ADA.

## Your next step

Find your most recent reading or lab result and place it in the chart above. If you have a meter, note the time of each check and whether you’d eaten. That pattern helps your doctor more than any single number. If your fasting reading is 100 or higher, ask about an A1C test. If you’d like some ready-made meals while you sort it out, our [free 7-day meal plan](https://nourishandstrong.com/free-plan) lays out a week for you. If you have diabetes, check any new eating plan with your care team first.

## Quick questions

### What blood sugar level is diabetic?

A fasting blood sugar of 126 mg/dL (7.0 mmol/L) or above, an A1C of 6.5% or above, or a 2-hour glucose tolerance result of 200 mg/dL or above is in the diabetes range, the CDC says. So is a random reading of 200 or above. A doctor usually confirms it with a second test on another day.

### What blood sugar level is too low?

Blood sugar below 70 mg/dL (3.9 mmol/L) is too low, and below 54 mg/dL (3.0 mmol/L) is severe, the CDC says. Treat a low with 15 grams of fast-acting carbs, such as half a cup of juice, and recheck after 15 minutes. Get emergency help if someone is confused, passing out or can’t swallow.

### Is a blood sugar level of 300 dangerous?

A blood sugar of 300 mg/dL is high and needs action. The ADA says to check your urine for ketones above 240 mg/dL and not to exercise if they’re present. Get emergency help if it comes with vomiting, stomach pain, fast breathing, fruity breath, drowsiness or confusion, or blood ketones of 1.6 mmol/L or higher.

### How high should blood sugar be before going to the hospital?

There’s no single blood sugar number that means go to the hospital. The NHS says to call 999 or go to A&E when high blood sugar comes with vomiting, stomach pain, fast breathing or heartbeat, drowsiness, fruity breath, confusion or high ketones. The ADA says blood ketones of 1.6 mmol/L or higher need emergency care right away.

### What are normal blood sugar levels for diabetics?

For many adults with diabetes, the American Diabetes Association suggests 80 to 130 mg/dL (4.4 to 7.2 mmol/L) before meals and under 180 mg/dL (10.0 mmol/L) at the peak after eating, with an A1C under 7%. Your care team may set different goals, depending on your health and medicines.

### What blood sugar is too low for a non-diabetic?

For someone without diabetes, a reading of 50 to 70 mg/dL can be normal, Cleveland Clinic says, and a single low reading usually isn’t a concern. The NHS says lows are rare without diabetes. If you also feel shaky, sweaty or confused, eat something with sugar and see your doctor if it keeps happening.

This article is general information, not medical advice. Blood sugar goals differ from person to person, and only your doctor can diagnose diabetes or set your targets. Get emergency help for confusion, passing out, a seizure, or high blood sugar with vomiting, fast breathing or high ketones. Don’t change any diabetes medicine without talking to your care team.

## Sources

- [CDC. Diabetes Testing](https://www.cdc.gov/diabetes/diabetes-testing/index.html)
- [CDC. Low Blood Sugar (Hypoglycemia)](https://www.cdc.gov/diabetes/about/low-blood-sugar-hypoglycemia.html)
- [American Diabetes Association. 6. Glycemic Goals and Hypoglycemia: Standards of Care in Diabetes, 2025](https://pmc.ncbi.nlm.nih.gov/articles/PMC11635034/)
- [American Diabetes Association. Diagnosis](https://diabetes.org/about-diabetes/diagnosis)
- [American Diabetes Association. Hypoglycemia (Low Blood Glucose)](https://diabetes.org/living-with-diabetes/hypoglycemia-low-blood-glucose)
- [American Diabetes Association. Hypoglycemia Symptoms and Treatment](https://diabetes.org/living-with-diabetes/hypoglycemia-low-blood-glucose/symptoms-treatment)
- [American Diabetes Association. Severe Hypoglycemia](https://diabetes.org/living-with-diabetes/hypoglycemia-low-blood-glucose/severe)
- [American Diabetes Association. Hyperglycemia (High Blood Glucose)](https://diabetes.org/living-with-diabetes/treatment-care/hyperglycemia)
- [American Diabetes Association. Diabetic Ketoacidosis (DKA)](https://diabetes.org/living-with-diabetes/dka)
- [Cleveland Clinic. Blood Glucose Test](https://my.clevelandclinic.org/health/diagnostics/12363-blood-glucose-test)
- [NHS. Low blood sugar (hypoglycaemia)](https://www.nhs.uk/conditions/low-blood-sugar-hypoglycaemia/)
- [NHS. High blood sugar (hyperglycaemia)](https://www.nhs.uk/conditions/high-blood-sugar-hyperglycaemia/)