About 40.1 million people in the United States have diabetes, roughly 1 in every 8 Americans. That number includes both people who know they have it and the more than 1 in 4 adults with diabetes who haven’t been diagnosed yet. When you add in the 115.2 million adults living with prediabetes, nearly half the adult population has some degree of blood sugar dysregulation.
Diagnosed vs. Undiagnosed Diabetes
The 40.1 million figure from the CDC captures both diagnosed and undiagnosed cases, but the split between those groups matters. Among U.S. adults surveyed between August 2021 and August 2023, 11.3% had a diabetes diagnosis they knew about, while another 4.5% met the clinical threshold for diabetes without ever being told they had it. That means for every three people managing their diabetes, there’s roughly one more person walking around with elevated blood sugar and no idea.
Undiagnosed diabetes is particularly concerning because chronically high blood sugar damages blood vessels, nerves, kidneys, and eyes whether or not you’re aware of it. The years between onset and diagnosis are not harmless waiting periods.
Type 1 vs. Type 2 Breakdown
The vast majority of diabetes in the U.S. is Type 2, which develops when the body becomes resistant to insulin or stops producing enough of it. An estimated 2.1 million Americans have diagnosed Type 1 diabetes, an autoimmune condition where the immune system destroys the cells that make insulin. Of those 2.1 million, about 1.8 million are adults and 314,000 are children and adolescents under 20. Type 1 accounts for roughly 5% of all diabetes cases, with Type 2 and other forms making up the rest.
Prediabetes: The Larger Hidden Number
Beyond the 40.1 million with diabetes, 115.2 million American adults, more than 2 in 5, have prediabetes. Their blood sugar is elevated above normal but not yet high enough for a diabetes diagnosis. What makes this number especially striking is that 8 in 10 of those people don’t know they have it.
Prediabetes is not a guaranteed path to Type 2 diabetes. Moderate weight loss, regular physical activity, and dietary changes can bring blood sugar back into the normal range. But without awareness, there’s no reason to make those changes, which is why the low detection rate is a public health problem in itself.
How Prevalence Varies by Age
Diabetes is overwhelmingly more common in older adults. Among Americans aged 18 to 34, just 1.3% have a diagnosed case. That figure rises steadily with age and reaches 20.1% among adults 65 and older, meaning roughly 1 in 5 seniors is living with the condition. Age-related insulin resistance, years of accumulated metabolic wear, and the gradual decline in the body’s ability to regulate blood sugar all contribute to this steep climb.
Where Diabetes Is Most and Least Common
Diabetes rates vary dramatically by state. In 2023, the highest age-adjusted prevalence among adults was in West Virginia (15.0%), Mississippi (14.7%), and Louisiana (14.5%). Puerto Rico and Guam both reached 16.0%. These areas share common threads: higher rates of poverty, limited access to healthcare, and fewer opportunities for physical activity and affordable nutritious food.
At the other end, Vermont (7.7%), Montana (7.9%), New Hampshire (7.9%), Colorado (8.0%), and Utah (8.0%) had the lowest rates. That’s still a significant burden, but it’s nearly half the prevalence seen in the hardest-hit states. The gap between the highest and lowest state rates is roughly double, underscoring how much geography, income, and local food environments shape diabetes risk.
The Economic Toll
Diabetes costs the U.S. an estimated $640 billion per year. That breaks down to $335 billion in direct medical spending (hospital visits, medications, insulin, monitoring supplies, treatment of complications) and $305 billion in indirect costs. The indirect figure includes 184 million lost workdays from people showing up to work but performing below capacity, 35 million lost workdays from absences, and roughly 993,000 individuals unable to work at all because of their condition. Premature death from diabetes accounted for another $148 billion in lost productivity from an estimated 288,000 deaths.
To put that in perspective, $640 billion exceeds the entire GDP of many mid-sized countries. It also means each person with diagnosed diabetes generates, on average, far higher healthcare costs than someone without the condition, a gap driven largely by complications like heart disease, kidney failure, and amputations.
Projections for the Coming Decades
The numbers are expected to keep climbing. Among young people under 20, CDC modeling projects that Type 1 cases could rise from about 166,000 in 2010 to over 200,000 by 2050 under a stable scenario, or to nearly 587,000 if incidence rates continue accelerating as they have in recent years. Type 2 diabetes in youth, once considered extremely rare, could quadruple to more than 84,000 cases by 2050 if current trends hold. These are projections for young people alone. The total adult burden is expected to grow substantially as the population ages and obesity rates remain elevated.