How Long Does an Autism Diagnosis Take?
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There is no set point in time where someone can learn they are autistic. Some people, like myself, learn they are autistic as a child while others are diagnosed as an adult. To be clear, there’s no wrong time to learn you are autistic and it’s fine to be diagnosed as an adult; however, what do you do if you are an adult and suspect you are autistic?
Pursuing an autism diagnosis in your adult years will be a big decision. It will not only change your life but also take some time to complete. If you think you are autistic and want to learn more about getting a diagnosis, then I recommend reading this post. It will cover what an autism diagnosis is, how long it takes, and what to do while waiting.
What Is an Autism Diagnosis?
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An autism diagnosis is a series of appointments to determine if someone is autistic. It’s a process involving questionnaires, contacting people that know the person well, and looking into their reports and medical history. You can get a diagnosis by having a medical practitioner or GP contact an autism specialist capable of performing the assessment.
A person is considered autistic if they meet certain criteria. For example, England uses the ICD-11, which considers someone autistic if they meet criteria for social communication differences and have features like a preference for routine and predictability.
If you suspect you are autistic, then it can be helpful to get a diagnosis. It can allow you to better understand yourself, get support where needed, and provide context for the way you experience the world. You’ll also learn where your strengths lie, which is valuable knowledge to have.
How Long Does an Autism Diagnosis Take?
There are multiple options you can pursue if you want an autism diagnosis. Here are some examples and how long they can take:
NHS
One method to get an autism diagnosis in the UK is through the NHS. The drawback is that an autism diagnosis through the NHS can take a while.
According to recent NHS statistics, 90.1% of patients with an open referral had theirs open for over 13 weeks, so over three months. A different NHS page mentions how people in the city of Leeds can expect a 27-month wait time to get their first appointment and another three months for the assessment to end.
The common thread in this data is how going the NHS route for an autism diagnosis is a commitment that will likely take months if not years. Fortunately, there are quicker options.
Private Services
Private neurodiversity assessment is faster than the NHS. How much faster will depend on the provider you approach. Assessment timelines through private providers can range from around 6–8 weeks depending on the service.
You may wonder why you would go the NHS route if private services are faster, but private services have some considerations. You will need to pay for the assessment yourself rather than having it covered. A private autism diagnosis may also not be recognised in the same way as one done by the NHS, so you may need to check whether your employer, GP, or local authority accepts private diagnoses.
Right to Choose
Another option for people in England is the Right to Choose. This is an NHS policy that allows you to choose which provider carries out your autism assessment, including approved private providers, while the NHS still covers the cost. This can significantly reduce waiting times compared to the standard NHS pathway.
To use Right to Choose, you’ll need to ask your GP to make a referral to your chosen provider. Not all areas or GPs are familiar with the process, so it can be helpful to have information ready about your chosen provider and their eligibility for NHS-funded assessments. Right to Choose is currently only available in England.
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What to Do While You Wait for a Diagnosis
An autism diagnosis is not a quick process and waiting will be required. Fortunately, there are some actions you can take while waiting for a diagnosis:
Track Your Traits
Consider recording which autistic traits you identify with, whether it’s social communication differences, a preference for routine, or focused interests. Your recorded observations can be used as evidence to support your assessment.
Take Online Tests
An online autism test can be a starting point for understanding your neurodivergent traits. They aren’t going to confirm autism the way a formal diagnosis does, but you can use them to learn about yourself. If you want to take an online test now, check out the one by Exceptional Individuals.
Workplaces can provide reasonable adjustments for neurodivergent employees. Consider looking into these to see if any of them would help you. You don’t need a formal diagnosis to request adjustments – you can explain that you are exploring a potential neurodivergent condition.
Join Support Groups
Autism support groups give you a chance to share your experiences with other people. Attending one of these can give you an idea of how other people responded to being in your position. You can also use these as a chance to connect with other autistic individuals.
Seek Coaching
A neurodiversity coach can give you a helping hand when figuring out how to navigate life as an autistic individual. They can provide advice and strategies at a time when you’re adjusting to understanding yourself better. If coaching interests you, then consider looking into Exceptional Individuals’ career training programmes.
Conclusion
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No matter which route you go, an autism diagnosis won’t be completed within a few days. You could go for the NHS route and have a free diagnosis that takes a long time, use Right to Choose to potentially speed things up, or go for a private service that’s quicker but costs money.
The only action I advise against is letting a lengthy wait discourage you from pursuing a diagnosis. Autism diagnoses have helped many people better understand themselves, and even if they aren’t a quick process, you should still pursue one if you think you are autistic.
Do you suspect you are autistic? Are you considering getting a diagnosis? Please let us know in the comments below.
Sources Cited
ICD-11 for Mortality and Morbidity Statistics (2022)
https://icd.who.int/browse/2025-01/mms/en#437815624
National Autistic Society (2026) What Can I Do While Waiting for an Autism Assessment
National Autistic Society (2026) How to Request an Autism Assessment
NHS (2022) What happens during an autism assessment
https://www.nhs.uk/conditions/autism/getting-diagnosed/assessments/
NHS (2022) How to get an autism assessment
https://www.nhs.uk/conditions/autism/getting-diagnosed/how-to-get-diagnosed/
NHS (2025) Autistic Diagnostic Service (LADS)
https://www.leedsandyorkpft.nhs.uk/our-services/autism-diagnostic-service-lads/
NHS Digital (2025) Autism Statistics, October 2024 – September 2025
