The GAD-7 (General Anxiety Disorder 7-item) scale is a assessment and diagnostic tool used by properly trained professionals to screen and assess the severity of general anxiety disorder. It should not be used in the place of a clinical assessment.
GAD-7 consists of 7 questions measured on a 4 point scale. Scoring can provide an assessment of the severity of anxiety with 4 ranges:

• Minimal anxiety
• Mild anxiety
• Moderate anxiety
• Severe anxiety

GAD-7 is a simple, short, well studied, and validated tool. It is available on PsychMeter for HIPAA/PHIPA compliant use. Signup or login to access the GAD-7.

Further reading for clinicians:

• A Brief Measure for Assessing Generalized Anxiety Disorder
• Does This Patient Have Generalized Anxiety or Panic Disorder?
• Generalized Anxiety Disorder
• Screening for anxiety disorders with the GAD-7 and GAD-2: a systematic review and diagnostic metaanalysis
• Psychometric properties of the GAD-7 and PROMIS-Anxiety-4a among youth with depression and suicidality: Results from the Texas youth depression and suicide research network
• Assessing Generalized Anxiety Disorder in Elderly People Using the GAD-7 and GAD-2 Scales: Results of a Validation Study