About 1 in 31 children in the United States has autism, according to the CDC’s most recent data from 2022. Applied to the country’s roughly 73 million children, that translates to an estimated 2.3 to 2.4 million kids on the autism spectrum. That number has risen sharply over the past two decades, driven largely by expanded screening, broader diagnostic criteria, and better awareness among parents and clinicians.
What the Latest CDC Data Shows
The CDC tracks autism prevalence through its Autism and Developmental Disabilities Monitoring (ADDM) Network, which collects data from 16 sites across the country. The most recent report, published in early 2025 using 2022 surveillance data, found a prevalence of 1 in 31 among 8-year-olds. That’s a notable jump from the previous report, which found 1 in 36 based on 2020 data.
The ADDM Network uses 8-year-olds as its benchmark because most children with autism have been identified and evaluated by that age. However, the same report found that among 4-year-olds, prevalence was also climbing, suggesting children are being identified earlier than in previous years. About 50% of 8-year-olds with autism had received a developmental evaluation by age 3, though that figure varied widely by location, ranging from 42% in Missouri to nearly 64% in Pennsylvania.
How Prevalence Has Changed Over Time
The rise in autism numbers over the past 25 years has been dramatic. When the CDC first began systematic tracking in 2000, the estimated prevalence was 1 in 150 children. By 2008 it had climbed to 1 in 88, by 2014 it was 1 in 59, and by 2018 it reached 1 in 44. The current figure of 1 in 31 represents roughly a fivefold increase since tracking began.
Most researchers attribute the bulk of this increase to changes in how autism is recognized and diagnosed rather than a true biological surge. The diagnostic criteria broadened significantly in 2013 when the DSM-5 consolidated several separate diagnoses (including Asperger’s syndrome and pervasive developmental disorder) into a single autism spectrum disorder category. Universal screening recommendations also expanded, and public awareness grew, meaning children who might have been overlooked in earlier decades, particularly girls and children of color, are now being identified. That said, scientists haven’t ruled out the possibility that some portion of the increase reflects a genuine rise in cases.
Who Gets Diagnosed
Autism is diagnosed roughly 3.5 to 4 times more often in boys than in girls. This gap has narrowed slightly in recent years as clinicians have gotten better at recognizing how autism presents differently in girls, who are more likely to mask social difficulties or display less obvious repetitive behaviors.
Racial and ethnic disparities in diagnosis have also shifted. Historically, white children were diagnosed at significantly higher rates than Black and Hispanic children. That gap has largely closed, and in some ADDM sites, Black children now have equal or even higher identified prevalence than white children. This likely reflects improved access to screening and greater awareness in communities that were previously underserved rather than a change in actual rates. Hispanic children and children from lower-income families still tend to be diagnosed later, with some not identified until school age.
When Children Are Typically Diagnosed
The median age of an autism diagnosis in the U.S. is about 47 months, or just under 4 years old. That varies considerably by region. In California, the median age of first diagnosis was 36 months, while in parts of Texas it was nearly 70 months, reflecting significant differences in access to developmental specialists and community awareness.
A large meta-analysis covering studies from 2012 to 2019 found the mean age at diagnosis to be about 60 months, or 5 years, though studies focused exclusively on children under 10 reported a lower mean of 43 months. The gap between when autism can be reliably detected (as early as 18 to 24 months) and when most children actually receive a diagnosis remains one of the biggest challenges in the field. Earlier identification allows earlier access to therapies and support services, which consistently leads to better outcomes.
How Screening Works
The American Academy of Pediatrics recommends that all children be screened for general developmental delays at 9, 18, and 30 months during routine well-child visits. On top of that, every child should be screened specifically for autism at 18 and 24 months, regardless of whether the pediatrician has any concerns.
The most commonly used tool at these visits is the Modified Checklist for Autism in Toddlers, or M-CHAT, a short parent-completed questionnaire designed to flag children at risk. If a child screens positive, the next step is typically a more detailed evaluation, which may involve a developmental pediatrician, psychologist, or multidisciplinary team. A formal diagnosis requires documented differences in social communication and interaction across multiple settings, plus at least two types of restricted or repetitive behaviors, such as intense fixation on specific interests, strong reactions to sensory input, or rigid adherence to routines.
Autism in the School System
One practical way to see autism’s footprint is through the education system. In the 2018-19 school year, about 7.1 million students ages 3 to 21 received special education services under the Individuals with Disabilities Education Act (IDEA). Autism accounted for roughly 11% of those students, or approximately 780,000 children and young adults. That number has certainly grown since then, given the continued rise in prevalence. Autism is now one of the fastest-growing categories of disability served in public schools, behind only specific learning disabilities, speech and language impairments, and other health impairments in total numbers.
These figures undercount the total number of children with autism, since not every diagnosed child qualifies for or receives special education services. Some children on the spectrum attend general education classrooms without formal support plans, particularly those with lower support needs.
Why the Numbers Vary by Location
Autism prevalence rates differ substantially depending on where you live. Some of that variation is real, but much of it reflects differences in diagnostic infrastructure, availability of specialists, state policies around screening, and how thoroughly health and education records are maintained. States with robust developmental surveillance systems and more specialists per capita tend to report higher rates, not because autism is more common there, but because it’s more consistently identified.
The CDC’s ADDM Network only covers 16 sites, so national estimates are extrapolations rather than a complete census. Rural areas and states with fewer pediatric specialists likely have significant numbers of undiagnosed children, meaning the true national prevalence could be higher than 1 in 31.