PHQ-9 Calculator: Depression Screening & Severity Score

Use the PHQ-9 Calculator: Depression Screening & Severity Score

Free PHQ-9 calculator: score all nine Patient Health Questionnaire items, grade depression severity from minimal to severe, and check the diagnostic algorithm.

How to Use PHQ-9 Calculator: Depression Screening & Severity Score

1. Step 1: Rate the nine symptoms

   For each of the nine questions, choose how often the symptom bothered you over the last two weeks: Not at all (0), Several days (1), More than half the days (2), or Nearly every day (3).

2. Step 2: Answer question 9 honestly

   The self-harm item is scored like the others, but any answer above Not at all displays crisis resources and deserves follow-up regardless of your total score.

3. Step 3: Complete the difficulty question

   Select how difficult these problems have made work, home life, or getting along with people. It is not added to the score, but the diagnostic algorithm formally requires at least Somewhat difficult.

4. Step 4: Read your score and severity band

   Your total (0-27) appears instantly with its severity band — minimal (0-4), mild (5-9), moderate (10-14), moderately severe (15-19), or severe (20-27) — plus the recommended clinical action.

5. Step 5: Check the algorithm and copy your summary

   Review the diagnostic algorithm result and the cognitive vs somatic subscores, then use Copy summary to save a dated record for tracking scores between appointments.

Key Features

• All nine official PHQ-9 items with 0-3 scoring
• Five severity bands with recommended clinical actions
• DSM-based diagnostic algorithm (second official scoring method)
• Cognitive-affective vs somatic symptom subscores
• Response, remission, and 5-point change thresholds
• Crisis resources shown for any positive answer on item 9

Understanding Results

How the PHQ-9 Calculator Scores Your Answers

The severity score is the sum of nine items, each rated 0 (not at all) to 3 (nearly every day) over the last two weeks, giving a 0–27 total. The separate diagnostic algorithm counts items scored 2 or higher — item 9 counts at 1 or higher — and requires a cardinal symptom (item 1 or 2): five or more endorsed symptoms suggests major depressive syndrome, while two to four suggests other depressive syndrome.

Reference Ranges & Interpretation

Severity bands from the original validation study (Kroenke et al., 2001): 0–4 minimal, 5–9 mild, 10–14 moderate, 15–19 moderately severe, 20–27 severe. A score of 10 or higher is the standard positive screen, with roughly 88% sensitivity and 85–88% specificity for major depression. During treatment, a 5-point drop is a clinically meaningful change, a 50% reduction counts as response, and a score below 5 counts as remission.

Assumptions & Limitations

The PHQ-9 is a screening and monitoring instrument, not a diagnosis. Its four somatic items (sleep, fatigue, appetite, psychomotor change) can be inflated by medical illness, medications, or sleep disorders; it cannot separate unipolar from bipolar depression; and item 9 is a safety flag, not a suicide risk assessment. Any positive screen — or any non-zero answer on item 9 — should lead to a conversation with a clinician.

Complete Guide: PHQ-9 Calculator: Depression Screening & Severity Score

A PHQ-9 calculator does more than add nine numbers: at a cutoff score of 10, the Patient Health Questionnaire-9 detects major depression with roughly 88% sensitivity and 85% specificity — yet most online versions show you only half of its scoring system. The PHQ-9 was designed with two separate readouts. The first is the familiar 0–27 severity score. The second is a symptom-count diagnostic algorithm that maps your answers directly onto the DSM criteria for a depressive episode, and it can flag a problem even when the severity score looks unremarkable. This guide walks through both methods, scores a realistic response set step by step, and explains what to do with the result — including the thresholds clinicians use to call a treatment “working.”

Two Scores From One PHQ-9 Calculator

Each of the nine questions asks how often a symptom bothered you over the last two weeks, scored 0 (not at all), 1 (several days), 2 (more than half the days), or 3 (nearly every day). That two-week window isn't arbitrary — it mirrors the DSM-5 requirement that symptoms persist for at least two weeks before a major depressive episode can be diagnosed. The nine items themselves map one-to-one onto the nine DSM diagnostic criteria: anhedonia, low mood, sleep disturbance, fatigue, appetite change, guilt or worthlessness, poor concentration, psychomotor change, and thoughts of self-harm.

Summing the items gives the severity score: 0–4 is minimal, 5–9 mild, 10–14 moderate, 15–19 moderately severe, and 20–27 severe. The algorithm method ignores the sum entirely. It counts how many individual symptoms crossed a frequency threshold and checks whether at least one of the two cardinal symptoms — anhedonia (item 1) or depressed mood (item 2) — is among them. Two readouts, two different questions being answered: “how heavy is the symptom load?” versus “does the symptom pattern resemble a depressive episode?”

A Worked Response Set, Scored Both Ways

Take a realistic answer pattern: item 1 scored 2, item 2 scored 1, item 3 scored 2, item 4 scored 3, item 5 scored 1, item 6 scored 2, item 7 scored 1, and items 8 and 9 scored 0. The severity sum is 2+1+2+3+1+2+1+0+0 = 12— squarely in the moderate band, where guidelines suggest a treatment plan built around counseling, follow-up, and possibly medication.

Now run the same answers through the algorithm. Four items reached the “more than half the days” threshold of 2 or higher: items 1, 3, 4, and 6. One of them is a cardinal symptom (item 1), but four endorsed symptoms fall short of the five needed for major depressive syndrome. The result: other depressive syndrome — a subthreshold pattern that still predicts real functional impairment and deserves follow-up. Same nine answers, two genuinely different clinical messages. That divergence is exactly why our calculator reports both, along with a cognitive-affective versus somatic subscore split that shows where the points came from.

The Diagnostic Algorithm Most Online Tools Skip

The algorithm's rules are short but strict. An item counts as “endorsed” only at a score of 2 or 3 — with one deliberate exception: item 9, the self-harm question, counts at any score of 1 or higher, because even occasional thoughts of death matter clinically. Major depressive syndrome requires five or more endorsed items including a cardinal symptom. Other depressive syndromerequires two to four endorsed items including a cardinal symptom. There's also a gate many people miss: the formal definition requires the tenth, unscored question — how difficult these problems have made work, home life, or relationships — to be answered at least “somewhat difficult.” Symptoms without functional impact don't constitute a syndrome.

Why bother with the stricter method? Specificity. A score of 11 built from nine scattered 1s and a single 2 describes a very different person than a score of 11 built from four symptoms present nearly every day. The severity sum treats them identically; the algorithm doesn't. In the original validation study, a PHQ-9 algorithm diagnosis of major depressive syndrome agreed with an independent mental-health-professional interview in 88% of cases.

PHQ-9 vs. PHQ-2: Which Screener, and When?

The PHQ-2 is simply the first two items of the PHQ-9 — the cardinal symptoms — scored 0–6. It exists for triage: a 30-second first pass in settings where administering nine items to everyone isn't practical. A PHQ-2 score of 3 or higher is a positive screen and the standard trigger for completing the full nine items. If that's where you are right now, start with our PHQ-2 calculator and come back here if it flags.

There's a third sibling worth knowing: the PHQ-4 combines the PHQ-2 with the GAD-2 anxiety screener into a single four-item check. Roughly half of people with major depression also meet criteria for an anxiety disorder, so pairing the two screens catches comorbidity a depression-only tool misses. Our PHQ-4 mental health calculator covers that combined snapshot, and the GAD-2 anxiety calculator handles the anxiety arm on its own.

What the Cutoff of 10 Actually Buys You

The threshold of 10 comes from Kroenke and Spitzer's original 2001 validation in 6,000 primary-care and obstetrics patients, where scores of 10 or above identified major depression with 88% sensitivity and 88% specificity. A 2019 individual-participant meta-analysis in the BMJ, pooling data from over 17,000 people, landed close by: 88% sensitivity and 85% specificity at the same cutoff. Meta-analytic work has since shown that cutoffs anywhere from 8 to 11 perform acceptably, which is why some health systems screen at 8 to favor sensitivity.

One number those headline stats hide: predictive value depends on how common depression is in the population being screened. In a typical primary-care clinic where perhaps 1 in 10 patients has major depression, a meaningful share of positive screens at the cutoff of 10 will be false positives — which is precisely why a positive PHQ-9 triggers a diagnostic interview rather than a prescription. Screening finds candidates; it doesn't issue diagnoses.

Response, Remission, and the 5-Point Rule

The PHQ-9's quiet superpower isn't screening at all — it's measurement-based care. Because the score moves reliably with clinical state, clinicians repeat it every 2–4 weeks during active treatment and read the trend against three fixed landmarks. A drop of 5 points is the accepted minimal clinically important difference — anything smaller may be measurement noise. Response means the score fell by at least 50% from baseline: an 18 becoming a 9, for instance. Remissionmeans the score sits below 5. A patient who starts at 18 and reaches 11 has improved meaningfully but hasn't yet responded; guidelines would call that a signal to adjust the plan — a dose change, a therapy referral, or both — rather than declare victory.

If you're using this tool between appointments, copy your summary each time and note the date. A run of scores — 16, 13, 9, 6 over eight weeks — tells a clinician far more than any single measurement, and it's exactly the data measurement-based care runs on. If you'd rather work through the nine items with a gentler, more conversational walkthrough first, our depression calculator presents the same instrument with plain-language guidance around each severity band.

Where the PHQ-9 Falls Short

Four of the nine items — sleep, fatigue, appetite, and psychomotor change — are somatic, and every one of them can be driven by things other than depression. Chemotherapy, pregnancy, chronic kidney disease, hypothyroidism, and plain sleep deprivation all inflate the somatic half of the score. That's why our calculator splits the cognitive-affective and somatic subscores: a 12 that's mostly items 3, 4, and 5 in a patient with a new medical illness warrants a different conversation than a 12 anchored on hopelessness and worthlessness.

Three more boundaries matter. First, the PHQ-9 cannot distinguish unipolar from bipolar depression — and antidepressant monotherapy in unrecognized bipolar disorder can precipitate mania, so a history of elevated-mood episodes changes everything about treatment. Second, item 9 is a single question about thoughts of death or self-harm; it flags risk but is not a suicide risk assessment, and any non-zero answer deserves direct human follow-up regardless of the total. Third, self-completed scores tend to run slightly higher than interviewer-administered ones, so a borderline result is best repeated before anyone acts on it. None of this makes the instrument weak — it makes it a screener, which is what it was always designed to be.

References

1. Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. 2001;16(9):606-613. PubMed
2. Levis B, Benedetti A, Thombs BD. Accuracy of Patient Health Questionnaire-9 (PHQ-9) for screening to detect major depression: individual participant data meta-analysis. BMJ. 2019;365:l1476. PubMed
3. Manea L, Gilbody S, McMillan D. Optimal cut-off score for diagnosing depression with the Patient Health Questionnaire (PHQ-9): a meta-analysis. CMAJ. 2012;184(3):E191-E196. PubMed

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