Normal blood sugar levels
Fasting, post-prandial and random, exactly as WHO and the American Diabetes Association publish them — in mg/dL and mmol/L, with the places the two disagree shown rather than smoothed over.
Nothing here can diagnose you, and nothing here is a treatment plan. Blood glucose results are interpreted by a doctor alongside your history, your symptoms and a repeat test — a single number on a screen is not a diagnosis. If any reading concerns you, or if you feel unwell, see a doctor rather than a website.
The American Diabetes Association criteria
These are the figures most Indian laboratories print beside a result.
| Result | Published value | Same value in mmol/L |
|---|---|---|
| Fasting plasma glucose — at least 8 hours with no food | ||
| Normal | 99 mg/dL or below | 5.5 mmol/L or below |
| Prediabetes | 100 to 125 mg/dL | 5.6 – 6.9 mmol/L |
| In the diabetes range | 126 mg/dL or above | 7.0 mmol/L or above |
| 2 hours into a 75 g oral glucose tolerance test | ||
| Normal | 139 mg/dL or below | 7.7 mmol/L or below |
| Prediabetes | 140 to 199 mg/dL | 7.8 – 11.0 mmol/L |
| In the diabetes range | 200 mg/dL or above | 11.1 mmol/L or above |
| HbA1c | ||
| Normal | below 5.7% | — |
| Prediabetes | 5.7% to 6.4% | — |
| In the diabetes range | 6.5% or above | — |
| Random (any time of day) | ||
| In the diabetes range | 200 mg/dL or above with the classic symptoms of high blood glucose | 11.1 mmol/L or above |
A result in the diabetes range is not a diagnosis. Published criteria require confirmation — normally a repeat of the same test on a separate day, unless someone has unmistakable symptoms with a clearly raised glucose. Your doctor makes that call, not a chart.
Source: American Diabetes Association, Standards of Care in Diabetes — Diagnosis and Classification of Diabetes. Diabetes Care 2025;48(Suppl. 1):S27–S49. Link
Source: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health — Diabetes Tests & Diagnosis. Link
The World Health Organization criteria
WHO publishes in mmol/L and uses the terms impaired fasting glucose and impaired glucose tolerance rather than prediabetes.
| Category | Fasting plasma glucose | 2 h after a 75 g glucose load |
|---|---|---|
| Diabetes | 7.0 mmol/L (126 mg/dL) or above | 11.1 mmol/L (200 mg/dL) or above |
| Impaired fasting glucose (IFG) | 6.1 – 6.9 mmol/L (110–125 mg/dL) | below 7.8 mmol/L (140 mg/dL), if measured |
| Impaired glucose tolerance (IGT) | below 7.0 mmol/L (126 mg/dL) | 7.8 – 11.0 mmol/L (140–199 mg/dL) |
WHO also accepts a random plasma glucose of 11.1 mmol/L (200 mg/dL) or above, in the presence of symptoms, and — since the 2011 consultation — an HbA1c of 6.5% or above. WHO is explicit that an HbA1c below 6.5% does not rule diabetes out.
Source: World Health Organization / International Diabetes Federation. Definition and diagnosis of diabetes mellitus and intermediate hyperglycaemia: report of a WHO/IDF consultation. Geneva: WHO, 2006. Link
Source: World Health Organization. Use of glycated haemoglobin (HbA1c) in the diagnosis of diabetes mellitus: abbreviated report of a WHO consultation. Geneva: WHO, 2011. Link
Where the two disagree — and it is only in one place
Prediabetes starts at a fasting glucose of 100 mg/dL
5.6 mmol/L · American Diabetes Association
The ADA sets the lower edge of impaired fasting glucose at 100 mg/dL, which classifies a much larger group of people as having prediabetes.
Impaired fasting glucose starts at 110 mg/dL
6.1 mmol/L · World Health Organization / IDF
WHO kept the higher cut-off. A fasting result of 105 mg/dL is prediabetes by American criteria and normal by WHO criteria — same blood, different rulebook.
Both figures are real and both are current. Which one your report uses depends on which guideline your laboratory or doctor follows. Every threshold above 126 mg/dL — the diabetes threshold itself — is identical in both.
"Normal sugar level by age" is not a published thing
It is the most searched version of this question, so here is the direct answer: no health authority publishes an age-banded normal range for blood glucose. Not WHO, not the ADA, not ICMR. The thresholds above apply to a 22-year-old and a 72-year-old alike.
The charts circulating online — 70–100 for one decade, 90–150 for another — appear to be a blend of two real things that have nothing to do with each other: average glucose observed in a population, which does rise with age because diabetes becomes more common, and individualised treatment targets for older adults who already have a diagnosis. Neither is a normal range.
Two things do genuinely differ, and both are covered on their own pages: pregnancy, where the thresholds are substantially lower, and the age at which routine screening is recommended, which is about who gets tested rather than what the result means.
The full explanation, and where those charts most likely came from →
The question as people search it, by age
Each page gives the same published criteria — because they are the same — and then what genuinely is different at that stage of life.
Fasting, post-prandial and random are three different tests
Fasting means at least eight hours with nothing but water. Post-prandial means two hours after a meal, timed from the first bite — and it is not the same as the two-hour value in a glucose tolerance test, which uses a standardised 75 g glucose drink so that everybody is challenged identically. Random means any time, with no reference to food; on its own it is a screening measurement rather than a conclusion.
The published two-hour thresholds of 140 and 200 mg/dL are written for the glucose tolerance test. Comparing a post-meal reading against them is common practice and it is not the same measurement. How each line on an Indian lab report was produced →
PeakForm is a training and accountability programme. It is not a treatment for diabetes or prediabetes, it is not a substitute for your doctor's advice, and nothing on this site should be acted on before speaking to one.
What this page will not do
It will not tell you what your result means. It will not tell you whether to be worried. It publishes no treatment targets, no diet prescriptions, no medicines and no "reverse it naturally" claims, because those are clinical decisions about a specific person and a web page is not in a position to make them.
What it can do is show you the criteria, name the bodies that published them, and be honest about where they disagree. Everything after that is a conversation with a doctor.
Common questions
What is a normal fasting blood sugar level?
What is a normal sugar level after eating?
Does the normal blood sugar range change with age?
Is one high reading enough to diagnose diabetes?
Thresholds from the ADA Standards of Care, NIDDK, the WHO/IDF 2006 consultation and the WHO 2011 HbA1c report. General information only — NOT medical advice, and never a diagnosis. Only a doctor can interpret your results and diagnose or treat diabetes. If a reading concerns you, see a doctor rather than a website. Every threshold, equation and glycemic index value used on this site is listed with its publication on the data & method page.