Diabetes Risk Calculator

Two different questions: where your numbers are now, and how likely you are to develop diabetes

Someone holding a lab report with a fasting glucose and an A1C needs a different answer from someone who has never been tested and simply wonders whether diabetes is likely. The calculator above answers both, and its two result cards at the top show the two answers side by side. Press the lab result card, then enter A1C, fasting plasma glucose and, if you have it, the 2-hour glucose from an oral glucose tolerance test. Each value is placed in the normal, prediabetes or diabetes range using the American Diabetes Association (ADA) criteria, and the highest range among your values becomes the overall result. The risk score card holds the Prediabetes Risk Test from the Centers for Disease Control and Prevention (CDC) and the ADA. It needs no blood draw: seven short questions give a score, and a score of 5 or higher means it is worth asking for a glucose test.

The two parts are deliberately separate. A questionnaire score tells you whether to get tested but never that you have diabetes. A lab value tells you where you stand on the day of the test. The score also shows how many points each answer earned, and how much of the total comes from items you can change in daily life. Nothing you type leaves your browser.

Why check even without symptoms

Diabetes is hard to notice before a test. The CDC's National Diabetes Statistics Report counts 40.1 million people in the United States with diabetes in 2023, diagnosed and undiagnosed together, or 12.0 percent of the population. Of the adults who have diabetes, 27.6 percent, about 11.0 million, have not been diagnosed.

Prediabetes is more common and even less visible. The CDC estimates that 115.2 million American adults, more than 2 in 5, have prediabetes, and 8 in 10 of them do not know it. Prediabetes is not diabetes, but as the Diabetes Prevention Program below shows, changing weight and activity at this stage cuts the number who go on to develop diabetes. Knowing early where you stand, and whether your risk is high enough to ask for a test, is what makes that possible.

• You have just received a lab report: enter the A1C or fasting glucose in the lab result card to see the range and how far the value sits from the next boundary.
• You are about to be tested, or have skipped testing for years: answer the questionnaire in the risk score card and see whether you reach 5 points. At 5 or more, it is worth asking for an A1C or fasting glucose test now.
• A parent or sibling is diagnosed, you move into an older age band, or your weight rises: each of these adds points to the score. The points per answer show which ones count most for you.

How to use the calculator

1. Pick a card. The two cards at the top show the result for the numbers you have entered so far, and each one is also a button that switches the view. The risk score questionnaire is open at first, and pressing the lab result card opens the lab report view. The other card's result stays visible.
2. Answer the questionnaire. Choose your sex and enter your age, height in feet and inches and weight in pounds; the tool turns them into BMI the same way the test's weight chart does. Then answer the questions about family history, blood pressure and activity. Women also see a question about gestational diabetes. The points earned by each answer appear at the end of its line.
3. Read the score stack. The points you earned pile up from the left. Solid pieces are items that are hard to change, such as age and family history. The hatched piece at the right end is the share from items you can change in daily life, activity and weight. The bands behind the bar show lower risk (0 to 4 points) and higher risk (5 or more), so you can see how far you are from the 5-point line.
4. Enter your lab values. In the lab report view, type the A1C in percent, the fasting glucose in mg/dL and, if you had a 75 g oral glucose tolerance test, the 2-hour result. One value is enough. If your report is in mmol/L, multiply by 18.016 to get mg/dL.
5. Read the range and the scale. Each line puts a marker on its scale and labels it normal, prediabetes or diabetes range. The overall result is the highest of them, and the calculator never averages a high value away. Under the A1C line you will find the estimated average glucose (eAG) and the IFCC value, and under the glucose lines the mmol/L value.
6. Copy the link if you want to return. Your numbers and the view you left open are stored only after the # in the address, which browsers never send to a server. Nothing is saved on this device.

ADA diagnostic criteria

The table shows the ADA Standards of Care in Diabetes 2026, section 2. Fasting means no food for at least 8 hours. The 2-hour value is measured after drinking 75 g of glucose. All glucose values are in mg/dL, and A1C is a percentage.

A random glucose of 200 mg/dL or higher also counts, but only in a person with classic symptoms of high blood sugar, such as extreme thirst, frequent urination and unexplained weight loss. Without those symptoms, one abnormal number is not enough. The Standards of Care require two abnormal results before a diagnosis when there is no unequivocal hyperglycemia: either two different tests from the same blood sample, or the same or a different test repeated on a separate sample. For example, an A1C of 6.6% together with a fasting glucose of 130 mg/dL from one blood draw would confirm the diagnosis, while a single borderline result would usually be repeated.

That is why the calculator says "diabetes range" and not "you have diabetes". It sorts a number into a band. The decision belongs to a clinician who knows how the sample was taken, how you feel and what other tests show.

Reading A1C as an average glucose

A1C measures the share of hemoglobin in red blood cells that has glucose attached, so it reflects roughly the last three months. The ADA publishes a conversion to an estimated average glucose: eAG (mg/dL) = 28.7 × A1C − 46.7 (Nathan and colleagues, 2008). The international unit used on many reports outside the United States is mmol/mol, and the NGSP gives the conversion IFCC (mmol/mol) = (A1C − 2.15) × 10.929. The calculator shows both under your A1C.

The eAG is an average and hides day-to-day swings. It also misleads when red blood cells live a shorter or longer time than usual. Anemia, inherited hemoglobin variants, pregnancy, kidney disease and a recent transfusion can all push A1C away from the true average, and in those cases clinicians lean on direct glucose measurements.

The Prediabetes Risk Test

The CDC and the ADA publish a short paper questionnaire that sorts people by their chance of having prediabetes and their risk of type 2 diabetes. Its own wording is: "a score of 5 or higher indicates you are at an increased risk for having prediabetes and are at a high risk for type 2 diabetes." The calculator follows the paper version. Because a man cannot have had gestational diabetes, the highest score you can reach here is 10.

Take a 52-year-old woman who had gestational diabetes, has a parent with diabetes, takes blood pressure medicine, is not active and has a BMI of 29.4. She scores 2 for age, 0 for sex, 1 each for gestational diabetes, family history, blood pressure and inactivity, and 1 for BMI, which makes 7 points. Two of those items, activity and weight, are within her reach. If she became active and lost enough weight to drop below a BMI of 25, she would lose 2 points. Even then she would sit at 5, the same threshold, which is why age and family history make regular testing sensible no matter how well the lifestyle items go.

The hatched piece of the score stack shows exactly that share. In this example it covers 2 of the 7 points (activity 1 and weight 1). With both at 0 she would still have 5 points, so she would remain in the higher-risk band of 5 or more. For her, getting tested comes first and lifestyle change goes alongside it. Someone whose hatched piece is most of the bar is in the opposite position, because the items they can change decide most of the score.

The BMI row has one special rule. For people of Asian descent the ADA uses a lower cut-off of 23, because the risk of type 2 diabetes rises at a lower body weight in these groups. The calculator therefore asks whether you are Asian American and adjusts the first two BMI bands.

Prediabetes can often be slowed or reversed

Prediabetes is a warning, not a verdict. In the Diabetes Prevention Program, a large US trial of adults at high risk, an intensive lifestyle program aimed at 7 percent weight loss and at least 150 minutes of physical activity a week reduced the incidence of diabetes by 58 percent. Metformin reduced it by 31 percent (Knowler and colleagues, New England Journal of Medicine, 2002). Lifestyle change beat the drug, and the amount of change needed was modest: a few kilograms and brisk walking most days.

If your numbers land in the prediabetes range, a sensible plan has three parts. First, aim for gradual weight loss of about 7 percent if you carry extra weight. Second, build up to 150 minutes of moderate activity a week, in sessions of any length. Third, repeat the blood test in about a year, or sooner if your clinician suggests it. Medicine is a conversation to have with a clinician, not something to decide from a web page.

How other countries draw the lines

The diagnostic thresholds for diabetes itself, a fasting glucose of 126 mg/dL, a 2-hour value of 200 and an A1C of 6.5 percent, are essentially shared worldwide. The differences lie in where "normal" ends and in the questionnaires used for screening. The other language versions of this calculator follow their own country's practice.

• United States and Korea: both start prediabetes at a fasting glucose of 100 mg/dL, the ADA cut-off used here. Korea uses a six-item Korean risk score and not the CDC test.
• Japan: normal fasting glucose is below 110 mg/dL, and the 100 to 109 band is called "high-normal".
• World Health Organization (WHO): impaired fasting glucose is defined as 110 to 125 mg/dL, so a fasting glucose of 105 is prediabetes under ADA rules but not under WHO rules.
• Europe: the Finnish Diabetes Risk Score, FINDRISC, is widely used. It adds waist circumference, diet and a previous high glucose to the picture, and it estimates a ten-year risk.

If your report comes from another country, check which cut-off its laboratory uses. A value that is "borderline" on one report may be plainly normal on another, even though the number is identical.

Common mistakes

• Entering a finger-stick reading as a lab value. A home meter measures capillary blood and can differ from a laboratory venous result by a wide margin. The diagnostic criteria apply to laboratory values.
• Counting breakfast as fasting. A fasting sample needs at least 8 hours without food. Coffee with milk or sugar breaks the fast, and plain water does not.
• Treating one abnormal number as a final diagnosis. Without symptoms, a second abnormal result is required. By the same logic, one normal result does not clear you for life.
• Trusting A1C alone. Conditions that change red blood cell lifespan make A1C unreliable. When A1C and glucose disagree, the glucose tests usually decide.
• Reading the questionnaire as a diagnosis. A score of 8 does not mean you have diabetes, and a score of 2 does not mean you do not. The score only decides whether you should ask for a test.

Limits and cautions

• The calculator is built for adults and for type 2 diabetes. It does not apply to children, to type 1 diabetes or to glucose testing during pregnancy, which uses different criteria.
• The range labels are a sorting of numbers against published cut-offs. They are not a diagnosis, which requires a clinician to weigh test conditions, symptoms and repeat results.
• The risk questionnaire was designed for screening in the United States. It estimates relative risk and has false positives and false negatives. If you already have a diagnosis of diabetes, the score has no meaning.
• The numbers you enter stay in this browser. They are placed only after the # when you copy the link, and they are not sent to a server or saved.

Sources checked The criteria and the questionnaire were checked on 2026-10-10, and the US statistics on 2026-10-19.

Sources

• 01American Diabetes Association: Standards of Care in Diabetes 2026, section 2, Diagnosis and Classification of DiabetesA1C, fasting and 2-hour criteria, the two-abnormal-results rule, prediabetes ranges
• 02CDC and ADA: Prediabetes Risk Test (paper version)Questions and point values for age, sex, gestational diabetes, family history, blood pressure, activity and weight
• 03CDC: How your Prediabetes Risk Test is scoredScore of 5 or higher means increased risk; BMI bands including the Asian American cut-off
• 04Nathan DM and colleagues: Translating the A1C assay into estimated average glucose values (Diabetes Care 2008)eAG = 28.7 × A1C − 46.7
• 05NGSP: IFCC and NGSP conversionIFCC mmol/mol = (NGSP % − 2.15) × 10.929
• 06Knowler WC and colleagues: Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin (N Engl J Med 2002;346:393)Lifestyle program 58 percent reduction, metformin 31 percent
• 07CDC: National Diabetes Statistics Report (content last reviewed Sept. 16, 2026)2023: 40.1 million people with diabetes (12.0 percent of the population), 27.6 percent of adults with diabetes undiagnosed (11.0 million), 115.2 million adults with prediabetes
• 08CDC: Prediabetes, Your Chance to Prevent Type 2 Diabetes115.2 million American adults, more than 2 in 5, have prediabetes; 8 in 10 adults with prediabetes do not know they have it

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