Home » Autism Diagnosis » What is the Average Age of Autism Diagnosis?

What is the Average Age of Autism Diagnosis?

May 13, 2024

There are many factors to consider when discussing the typical age of autism diagnosis because children on the autism spectrum range in age, socio-economic group, race, gender, etc. Due to these factors and others in the general population, children with autism spectrum disorder (ASD) can be reliably diagnosed as early as three to ten years old.

What is the Average Age of Autism Diagnosis?

Is early detection of autism better?

There are many cases of delayed recognition of individuals not being identified with an autistic disorder until they are school age to young adults because the symptoms of autism aren’t prevalent until they are in a classroom setting. There are many reasons that this delayed diagnosis can occur at an older age and can affect the individual differently than if they had an earlier one and early intervention was initiated.

When autism spectrum disorders are diagnosed earlier, in young children, there are early behavioral interventions, occupational therapy, and other therapies that can be a part of the child’s plan and help with developmental disorders and other disabilities that may have been identified along with autism.

What can help?

Providing resources for parents and caregivers about autism and the benefits of early diagnosis would help children with ASD and get them on a treatment plan sooner. This could also help the parents and caregivers give the child what they need and be supportive.

Special Offer

Don't miss out on the Autism Parenting Summit.
Click here to sign up now!

Better access to resources and information could also increase the effectiveness of the child’s treatments and therapies. It would give the child more opportunities and take advantage of a younger brain hard wired to learn and flex with environment and care.

What is the common age of diagnosis for children with autism worldwide?

There are studies that suggest the average age of children diagnosed with autism is around three years old in both the United States (US) and in the United Kingdom (UK). When it comes to other similar diagnoses, such as pervasive developmental disorder, the average diagnosis age is five years old in the US and around six years old in the UK.

Most children diagnosed with asperger’s syndrome have an average age of seven years old in the US and nine years old in the UK. Studies suggest that the differences in regions, poverty, children with multiple diagnoses and the diagnostic criteria for these children to be diagnosed is different in various regions and the ability to properly diagnose disorders can vary.

Where can furthering education of autism and resources take early detection of ASD?

Although lack of mental health resources and continuous pediatric care can affect diagnosing a child earlier, there is always new information expanding what is being learned about autism spectrum disorder. Continuing physician education and having special services in place for families with concerns for their children can benefit these families.

For example, The Great Start initiative of Michigan is for families with young children that have concerns over their children’s development and gives guardians and caregivers tools to use at home. They have programs that include home visits, playgroups, Early On and referral services to support families of children that have developmental delays and fall within the poverty line.

What are the main three symptoms of autism?

Three of the key early indicators of autism are as follows:

  • Not reaching developmental milestones when a child is expected to
  • Social awkwardness/lack of social skills
  • Having some form of repetitive behavior like hand flapping, lining up toys, or even the repetition of schedules and routines

What are some roadblocks for autism diagnosis?

Some of the roadblocks to diagnosing at a younger age for a child with autism can include whether they live in a rural or urban setting. In a study, there were findings that a child in a rural setting could be diagnosed almost six months before their urban counterpart.

Other children that are at or below the poverty level were diagnosed almost a year later than children above the poverty line. This could be for many reasons like lack of transportation or having access to a constant family practitioner or pediatrician.

Are there things parents can look for?

Studies have shown children that have a severe delay in language and social awareness, hand flapping, toe walking, and demonstrate “odd play” sustained over a period of time are diagnosed a little over a year sooner than others. The mean age of diagnosing autism is made younger with developmental disabilities that have already existed that could coincide with autism.

Most of the roadblocks listed above can be remedied through further education for physicians, educators, guardians, caregivers, early childhood educators, and anyone who works with younger children. Also, having supports and services in place is vital for people who have questions and concerns to be able to take the steps necessary and have their questions answered.

Who can parents talk to when they have concerns?

It is recommended that families who think their child might need an autism diagnosis speak with one or all of the following:

  • Family physician or pediatrician
  • Teacher (Early Childhood and Elementary)
  • Local mental health center
  • Local support group

What is the average age of diagnosing autism in boys versus girls?

According to the Center for Disease Control, children that are identified on the autism spectrum  are one in 44. It is also stated that boys are four times more likely to have an autism diagnosis than girls.

The average age of diagnosis in girls is four years old, in comparison to a little over three years old  for boys. That shows that most boys are diagnosed before girls and more frequently.

Why the delay for diagnosing girls with autism?

The delay of diagnosing girls usually happens for many reasons. One thought is that their symptoms may not be as severe and they may have the ability to mask their symptoms.

Also, in one autism study of boys and girls, the results were that girls had a harder time with social cognition and interpreting social cues. Whereas boys had more repetitive behaviors like hand flapping and an extreme narrow scope of interests.

Was it the same when the boys and girls were older?

It wasn’t until the study looked at older boys with autism spectrum disorders, 10-15 years old, that they had a harder time with social cues and using language appropriately in social situations. Whereas, with girls, that seemed to be the main symptom that could be studied.

So, it seems that the symptoms that girls have are not as easily seen and detected as they are with boys. The boys had more physical symptoms and girls were more internal and social in nature.

How will autism look in a family?

Every person with autism spectrum disorder is different and the services they need can also be different. The recommendation would be to speak with one of the trusted resources listed above as they can lead an individual in the direction they need to get their children the resources and support required.

With the correct supports in place for the child and their family, the child could see improvement with social abilities and other areas they could work on. The earlier autism can be diagnosed, the sooner the child and their family can receive the help and support they need.


American Academy of Pediatrics. (2015). Age at autism diagnosis differs between boys, girls. ScienceDaily https://www.sciencedaily.com/releases/2015/04/150428082155.htm 

Brett, D., McConachie, H., Parr, J. & Warnell, F. (2016). Factors Affecting Age at ASD Diagnosis in UK: No Evidence that Diagnosis Age has Decreased Between 2004 and 2014.                                                             




Mandell, D., Novak, M. & Zubritsky, C. (2010). Factors Associated With Age of Diagnosis Among Children With Autism Spectrum Disorders.                                    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861294/

Support Autism Parenting Magazine

We hope you enjoyed this article. In order to support us to create more helpful information like this, please consider purchasing a subscription to Autism Parenting Magazine.

Download our FREE guide on the best Autism Resources for Parents

Related Articles

Autism Parenting Magazine