Based on the most recent CDC data, roughly 1 in 36 children in the United States has autism spectrum disorder, and an estimated 2.21% of American adults are on the spectrum. Applied to the current U.S. population, that puts the total number of people living with autism well into the millions. The number has risen dramatically over the past two decades, driven largely by broader diagnostic criteria, better screening, and increased awareness across racial and ethnic groups.
Current Prevalence in Children
The CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network tracks autism prevalence among 8-year-olds, the age considered most reliable for population-level estimates. The most recent complete surveillance data, from 2020, found a prevalence of 27.6 per 1,000 children, or about 1 in 36. A newer 2022 cycle from an expanded 16-site network puts the figure even higher at roughly 1 in 31, or 3.2% of 8-year-olds.
To put that in perspective: in the year 2000, the CDC identified 1 in 150 children with autism. By 2010 it was 1 in 68. The rate has roughly quadrupled in two decades.
Estimated Adults Living With Autism
A 2017 CDC study estimated that 2.21% of U.S. adults have autism. That percentage varied by state, from a low of 1.97% in Louisiana to a high of 2.42% in Massachusetts. Because most adults on the spectrum were never formally diagnosed as children, especially those born before routine screening became common, exact counts are harder to pin down than they are for kids. But 2.21% of the roughly 260 million American adults translates to approximately 5.7 million people.
Boys, Girls, and the Narrowing Gap
Autism is still identified far more often in boys. The 2022 ADDM data found a prevalence of 49.2 per 1,000 among boys compared with 14.3 per 1,000 among girls, a ratio of about 3.4 to 1. That ratio has been shrinking: it was 4.2 to 1 in 2018, then 3.8 to 1 in 2020.
The narrowing ratio might look like progress in identifying girls, but the picture is more complicated. The actual gap in raw numbers between boys and girls has widened over the same period, from a difference of 27.7 per 1,000 in 2018 to 34.9 per 1,000 in 2022. In other words, the ratio is shrinking mainly because prevalence among boys is climbing so fast, not necessarily because identification of girls has caught up.
Racial and Ethnic Differences Have Reversed
For years, white children were identified with autism at higher rates than children of other racial and ethnic backgrounds, a pattern widely attributed to unequal access to evaluation and diagnosis. That pattern has now flipped. In the 2020 surveillance data, prevalence was lowest among white children (24.3 per 1,000) and highest among Asian or Pacific Islander children (33.4 per 1,000). Black children (29.3 per 1,000) and Hispanic children (31.6 per 1,000) also had higher rates than white children.
This reversal likely reflects improved outreach, screening, and diagnostic access in communities that were historically underserved rather than an actual shift in who develops autism.
Why the Numbers Keep Rising
The steep upward trend does not necessarily mean autism itself is becoming more common. Several overlapping factors explain most of the increase.
- Broader diagnostic criteria. The shift to updated diagnostic standards changed who qualifies for a diagnosis. When researchers applied the newer criteria retroactively to a 2008 dataset, the estimated prevalence dropped from 11.3 per 1,000 to 10.0 per 1,000, roughly a 12% decrease. Over time, though, clinicians adapted their documentation to match the new framework, and counts continued to rise.
- Earlier and wider screening. More children are being evaluated at younger ages, and communities that previously under-identified autism, particularly among minority populations, are now catching up.
- Greater awareness. Parents, teachers, and pediatricians are more likely to recognize signs of autism and refer children for evaluation than they were 20 years ago.
Researchers have not ruled out a genuine increase in the underlying rate, but the consensus is that most of the growth in reported cases comes from better detection.
Wide Variation Across States and Regions
Where you live dramatically affects how likely a child is to be identified. Across the 16 ADDM sites in the 2022 data, prevalence among 8-year-olds ranged from 1 in 103 in the Laredo, Texas area to 1 in 19 in California. That fivefold difference is enormous, and it does not reflect real differences in how many children are autistic. Instead, it reflects differences in the availability of evaluation services, local diagnostic practices, and how thoroughly schools and healthcare providers document developmental concerns.
Testing gaps illustrate the problem. Across all ADDM sites, 66.5% of children identified with autism had a documented autism-specific evaluation on file, but that figure ranged from just 24.7% in New Jersey to 93.5% in Puerto Rico. In communities with less testing, many children with autism simply never appear in the data.
The Economic Scale
The financial cost of autism in the United States is substantial. A CDC-published forecast estimated that combined costs, including medical care, special education, residential services, employment support, and lost productivity for both autistic individuals and their parents, would reach $461 billion annually by 2025. That represents roughly 1.6% of U.S. GDP. A decade earlier, in 2015, the same researchers estimated the burden at $268 billion. The increase is driven both by rising prevalence and by the growing number of autistic children aging into adulthood, where long-term support costs accumulate.