Informal online tests abound to determine learning styles and aptitudes, sometimes as a precursor to evaluating a learning disability, but the National Center for Learning Disabilities recommends a formal evaluation to diagnose any learning disorder. Parents can obtain such an evaluation for children at no cost under the Individuals with Disabilities Education Act. Adults who suspect they have a learning disability may need to pay for initial evaluation themselves. The process involves some combination of interviewing, observation and test-taking administered by a licensed professional, who, depending on the outcome, provides the documentation of any learning disability found. Online tests, while interesting, will not substitute for this documentation of formal evaluation. You will need documentation to pursue treatment, if any, and to obtain accommodation in classes and standardized testing.