A person with an intellectual disability usually has an IQ score below 70. There are several levels of severity: - Mild: IQ between 50-70 - Moderate: IQ between 35-50 - Severe: IQ between 20-35 - Profound: IQ below 20 But IQ is just one way to assess intellectual disability.  A person with an intellectual disability could also have low functional and adaptive skills. These skills involve the ability to do day-to-day activities.