About PHQ-9 Depression Screening
The PHQ-9 calculator turns the nine-question Patient Health Questionnaire into an objective depression severity score, making it one of the most widely used screening tools in primary care and mental health clinics worldwide. Each item maps to a DSM-5 criterion for major depressive disorder and asks how often, over the last two weeks, symptoms such as low mood, sleep disturbance, fatigue, poor concentration, or thoughts of self-harm have bothered you. Scores range from 0 to 27, and the tool immediately classifies the result as Minimal (0-4), Mild (5-9), Moderate (10-14), Moderately Severe (15-19), or Severe (20-27). A 2010 meta-analysis in the British Medical Journal found that, at a cutoff of 10 or above, the PHQ-9 has a pooled sensitivity of 78% and specificity of 87% for detecting major depression. Because it is short, self-administered, and free, it is ideal for tracking symptoms between appointments, evaluating response to therapy or medication, and starting a data-driven conversation with a clinician.
How It Works
You answer nine items, each scored from 0 (not at all) to 3 (nearly every day). The calculator sums the responses into a total score and compares it against standardized severity bands. Item 9, which asks about thoughts of self-harm, is especially important: any score above 0 on that item should prompt immediate contact with a mental health professional or crisis service. The result is returned in seconds and gives both a numeric score and a plain-language severity label.
Formula & Calculation Logic
The PHQ-9 is additive: Total Score = Σ(item 1 through item 9), where each item contributes 0, 1, 2, or 3 points. There are no weights or multipliers. Cutoffs follow Kroenke and colleagues' original validation: 0-4 minimal, 5-9 mild, 10-14 moderate, 15-19 moderately severe, 20-27 severe. The calculator assumes responses describe the past two weeks and that all items are answered.
Step-by-Step Guide
- Step 1: Read each of the nine PHQ-9 items carefully.
- Step 2: Choose a score from 0 to 3 based on how often each symptom affected you in the last two weeks.
- Step 3: Enter all nine responses into the calculator.
- Step 4: Click Calculate to see your total score and severity category.
- Step 5: Review item 9 separately; if it is greater than 0, reach out to a clinician or crisis service right away.
Example Calculations
- Scenario 1: A user selects mostly 1s and 2s, totaling 11 points, which falls in the Moderate range and suggests a clinical evaluation is appropriate.
- Scenario 2: A user scores 0 on items 1-8 but 2 on item 9; even though the total is only 2, the self-harm item indicates immediate professional support is needed.
Common Use Cases
- Screening for depression during a primary care visit or telehealth intake.
- Tracking symptom changes every two weeks during therapy or antidepressant treatment.
- Monitoring mental health trends in workplace wellness programs.
- Generating a printable score to discuss with a psychologist or psychiatrist.
Pro Tips
- Answer based on the last two weeks, not your lifetime experience of mood symptoms.
- Do not use the PHQ-9 alone to make treatment decisions; combine it with clinical judgment.
- Re-test at regular intervals to measure improvement or detect early relapse.
- Share the full nine-item breakdown with your provider, not just the total score.
Common Mistakes to Avoid
- Interpreting any PHQ-9 score as a formal diagnosis.
- Ignoring a non-zero score on the self-harm item because the total is low.
- Comparing scores taken months apart without noting life stressors or treatment changes.
- Rounding all answers to the middle value instead of choosing the response that best fits each item.
Why Use This Tool?
- Provides a quick, evidence-based depression severity score in under a minute.
- Helps clinicians and patients track treatment progress with objective numbers.
- Free, self-administered, and validated across many languages and cultures.
- Flags urgent suicide-risk items that need immediate attention.