About 1 in 31 children in the United States has autism spectrum disorder, or roughly 3.2% of eight-year-olds. That figure comes from the CDC’s most recent surveillance data, collected in 2022 through its Autism and Developmental Disabilities Monitoring (ADDM) Network. The rate has risen dramatically over the past two decades and continues to climb.
How the Rate Has Changed Over Time
When the CDC first began tracking autism prevalence in 2000, about 1 in 150 eight-year-olds met the criteria. By 2012, the estimate had reached 1 in 69. In 2018, it was 1 in 44. Now, at 1 in 31, the trajectory shows no signs of leveling off.
The increase doesn’t necessarily mean autism itself is becoming more common in a biological sense. Broader diagnostic criteria, greater public awareness, better screening in schools and pediatric offices, and improved identification among girls and children of color all contribute to higher numbers. That said, researchers haven’t ruled out the possibility that some of the rise reflects a genuine increase in cases, potentially linked to environmental or genetic factors that aren’t yet fully understood.
Boys, Girls, and the Diagnosis Gap
Boys are diagnosed with autism nearly four times as often as girls, with a male-to-female ratio of about 3.8 to 1. For boys, the prevalence is roughly 4.3%, compared to about 1.1% for girls. That gap is real, but it has been narrowing. In the CDC’s earliest surveillance reports, girl prevalence barely registered. The most recent data marked the first time overall prevalence among girls exceeded 1%.
Part of the historical undercount in girls likely stems from how autism presents differently across sexes. Girls are more likely to mask social difficulties or display subtler repetitive behaviors, making them harder to identify using tools originally developed around male presentation. As clinicians become more attuned to these differences, more girls are being recognized.
Rates Vary Widely by Location
Where a child lives can dramatically affect whether they receive an autism diagnosis, at least on paper. Among the 16 sites tracked by the ADDM Network in 2022, California reported the highest prevalence at about 53 per 1,000 children (roughly 1 in 19), while Laredo, Texas, reported the lowest at about 14 per 1,000 (roughly 1 in 70). Pennsylvania, Wisconsin, and Minnesota also reported rates well above the national median.
These differences don’t mean autism is more common in California than in Texas. They more likely reflect differences in access to developmental screening, the availability of specialists, how school systems identify and serve children, and the way local records are kept. Communities with robust early-intervention programs and well-resourced school systems tend to identify more children. Areas with fewer resources or where families face language and cultural barriers tend to undercount.
When Children Are Diagnosed
The median age of a first autism diagnosis in the US is about 47 months, just under four years old. That varies enormously by location. In California, the median drops to 36 months, while in parts of Texas it stretches to nearly 70 months, meaning some children aren’t formally diagnosed until close to age six.
Only about half of children who are eventually diagnosed with autism receive a developmental evaluation by age three, the window when early intervention is most effective. In Pennsylvania, that figure reaches nearly 64%, while in Missouri it drops to about 42%. Earlier identification tends to lead to better outcomes because therapies targeting communication and social skills have the greatest impact during early brain development.
Autism in Adults
Most prevalence headlines focus on children, but autism is a lifelong condition. A 2022 study published in the Journal of Autism and Developmental Disorders estimated that about 5.4 million US adults, roughly 2.2% of the adult population, are on the autism spectrum. That works out to about 1 in 45 adults aged 18 to 84.
Many of these adults were never diagnosed as children, particularly those who grew up before modern screening became routine. Some received other diagnoses, like intellectual disability or social anxiety, that may have overlapped with or obscured an autism diagnosis. A growing number of adults are now seeking evaluation for the first time, often after recognizing themselves in descriptions of autism or after a child in their family is diagnosed.
The Economic Scale
Autism carries substantial costs for families and for society at large. The estimated lifetime social cost per person with autism is about $3.6 million, a figure that includes healthcare, education, lost productivity, and support services across a full lifespan. Between 1990 and 2019, roughly 2 million new cases were diagnosed in the US, generating an estimated $7 trillion in cumulative social costs. If current prevalence holds steady through 2029, that total is projected to reach $11.5 trillion. If prevalence continues rising at its recent pace, the figure could approach $15 trillion.
How Autism Is Defined and Counted
The current diagnostic framework, the DSM-5, requires two core features for an autism diagnosis. The first is persistent difficulty with social communication and interaction: trouble with back-and-forth conversation, limited use of nonverbal cues like eye contact and gestures, and challenges forming and maintaining relationships. The second is a pattern of restricted or repetitive behaviors, which can include repetitive movements or speech, rigid routines, intensely focused interests, or unusual sensitivity to sensory input like sounds, textures, or lights. A person needs to show difficulties in all three areas of social communication plus at least two types of repetitive behavior.
Autism exists on a spectrum, and the DSM-5 assigns one of three severity levels based on how much support a person needs. Some individuals live independently with minimal accommodations, while others require substantial daily assistance. The CDC’s ADDM Network counts cases by reviewing health and education records across its monitoring sites rather than relying on parent surveys, which is why its estimates are considered among the most rigorous available. The network covers selected communities in participating states, not the entire country, so the national figure is an extrapolation from those sites.