Depression Index Calculator
Compute a 0–10 depression-symptom index by combining inverted mood, energy, and direct social-withdrawal ratings. Useful for personal tracking; not a clinical diagnosis.
Last updated: May 2026
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About this calculator
The formula is Depression Index = (22 − mood_rating − energy_level + social_withdrawal) / 3, where each input is rated 1–10. Mood and energy are subtracted from 11 each (combined: 22 − mood − energy = (11 − mood) + (11 − energy)) so that low ratings (depressed-feeling, low energy) produce high symptom contributions; social_withdrawal enters directly so that high values (more isolation) contribute more. The output is divided by 3 to give a single number nominally on a 0–10 scale. The mathematical range: minimum (best case) is (22 − 10 − 10 + 1)/3 = 3/3 = 1.0; maximum (worst case) is (22 − 1 − 1 + 10)/3 = 30/3 = 10.0. So the practical range is ~1 to 10, not 0 to 10. Edge cases: the formula gives equal weight to all three dimensions, which doesn't match clinical reality where loss of interest (anhedonia) and persistent low mood are the two core diagnostic criteria for major depressive disorder, while social withdrawal is a behavioural symptom often secondary to them. The three-item structure omits other diagnostic criteria (appetite changes, sleep disturbance, concentration, feelings of worthlessness, thoughts of death) and so is best treated as a quick personal-tracking metric, not a screening or diagnostic instrument. Validated tools like PHQ-9 (Kroenke 2001) have 9 items, established cut-offs (5/10/15/20 = mild/moderate/moderately severe/severe), and are recommended for any clinical decision.
How to use
Example 1 — mild depressive symptoms. mood_rating 6, energy_level 5, social_withdrawal 4. Step 1: 22 − 6 − 5 + 4 = 15. Step 2: 15 / 3 = 5.0. Verify: a score of 5.0 sits in the middle of the 1–10 range, consistent with the inputs — mood and energy slightly below average, modest withdrawal — suggesting some depressive symptoms worth monitoring but not yet at a critical level. For a clinical comparison, validated PHQ-9 with similar self-ratings would likely score in the 5–9 range (mild depression band) ✓. Example 2 — significant depressive symptoms. mood_rating 3, energy_level 2, social_withdrawal 8. Step 1: 22 − 3 − 2 + 8 = 25. Step 2: 25 / 3 ≈ 8.33. Verify: 8.33 is near the high end of the 1–10 range, signalling substantial depressive-symptom burden across all three dimensions — low mood, low energy, and high withdrawal all present at concerning levels. This profile would map to roughly moderate-to-severe on PHQ-9 (likely 15–20+), and warrants prompt professional evaluation. If this score persists over 2+ weeks, talking to a GP, psychologist, or psychiatrist is the appropriate next step — and any thoughts of self-harm or suicide require immediate contact with a crisis service ✓.
Frequently asked questions
How does this score map onto validated depression screening tools?
PHQ-9 (Patient Health Questionnaire, Kroenke et al. 2001) is the most widely-used validated brief depression screen, with 9 items scored 0–27 and cut-offs at 5 (mild), 10 (moderate), 15 (moderately severe), and 20 (severe). PHQ-9 covers all 9 DSM-5 criteria for major depressive disorder including appetite changes, sleep disturbance, concentration problems, psychomotor changes, and importantly thoughts of self-harm. This calculator covers only three rough dimensions (mood, energy, social withdrawal) and does not screen for suicidal ideation — a critical gap that means it should never be used as the only check on someone with concerning symptoms. A rough mapping: a calculator score of 5 ≈ PHQ-9 mild (5–9); 7 ≈ moderate (10–14); 9+ ≈ moderately severe to severe (15+). Other validated tools include the Beck Depression Inventory (BDI-II, 21 items, used in research and clinical practice), the Hamilton Depression Rating Scale (HAM-D, clinician-administered), and the QIDS-SR for clinical follow-up. For any clinical concern, use PHQ-9 (free, takes 2 minutes) and discuss with a healthcare provider.
Why are mood and energy inverted but not social withdrawal?
Self-rated wellness scales typically follow the convention 'higher = better' for positive constructs (mood, energy) and 'higher = more of the symptom' for negative ones (withdrawal, avoidance). The formula needs all inputs in the same direction to average them sensibly. Mood and energy are wellness ratings on the 'higher is better' convention, so they're inverted (subtracted from 11) to convert to symptom contributions where higher means worse. Social withdrawal is already rated such that higher means worse (more withdrawal = more symptom), so it enters directly. The combined transformation 22 − mood − energy = (11 − mood) + (11 − energy) keeps the math symmetric. Without these inversions, a person feeling great (mood 10, energy 10, withdrawal 1) would have the highest score, making the index meaningless. Same trick appears in the calculator's stress-level and burnout-risk formulas, which invert their wellness inputs in the same way.
Why doesn't this calculator screen for suicidal ideation?
It doesn't include a thoughts-of-self-harm or suicide item, which is a serious limitation — validated tools like PHQ-9 always include this question because identifying acute risk is the single most important reason to screen for depression. The absence of this item in a three-question calculator means it can give a 'low' score while missing critical risk. If you or someone you know has any thoughts of self-harm or suicide, contact emergency services immediately: in the US call or text 988 (Suicide and Crisis Lifeline); in the UK call 116 123 (Samaritans), 999 for emergency, or NHS 111; in the EU 116 123; in Australia call 13 11 14 (Lifeline). Do not rely on a self-tracking tool to assess whether intervention is needed when these thoughts are present. PHQ-9's question #9 explicitly asks about 'Thoughts that you would be better off dead or of hurting yourself' and is the clinical standard; any 'yes' answer triggers immediate follow-up regardless of total score.
What are the common mistakes when using depression self-ratings?
The biggest mistake is rating only on bad days, which inflates the score and reinforces a depressed view; pick a fixed weekly time and rate the past 7 days as a whole. The second is treating low scores as proof you're fine when other features are present — depression often manifests as physical symptoms (chronic fatigue, GI upset, headaches), irritability rather than sadness, or social withdrawal that the person rationalises as 'just being busy', and a single screen can miss these. The third is using a single snapshot to decide on starting or stopping antidepressant medication; medication decisions need clinical assessment, history, and ongoing monitoring. People also confuse sadness with depression — sadness in response to an obvious loss is normal grief, while depression is pervasive low mood with anhedonia persisting beyond the triggering context. Ignoring physical health is another error: thyroid disease, anaemia, vitamin D and B12 deficiency, low testosterone, and many medications can mimic depression. Finally, missing suicidal ideation by using a tool that doesn't ask about it is the most dangerous mistake — use PHQ-9 or talk to a clinician when in doubt.
When should I not use this calculator?
Do not use it if you have any active thoughts of self-harm or suicide — contact emergency services or a crisis line immediately (988 in the US, 116 123 in the UK). It is not appropriate as a diagnostic tool for major depressive disorder, bipolar disorder, persistent depressive disorder, postpartum depression, or seasonal affective disorder — those require clinical assessment with validated instruments and history. It is not validated for children or adolescents (use PHQ-A or other age-specific screens), or during pregnancy and postpartum (use EPDS, the Edinburgh Postnatal Depression Scale). Do not use it for medication decisions — those need clinical input, not self-tracking. The three-item structure is insufficient for proper screening; for any concerning symptom or persistent low mood lasting more than 2 weeks, use PHQ-9 (free, 9 items, validated) or see your GP. Finally, do not use it as a workplace surveillance tool — mental health screening by employers is ethically fraught and biases self-reports; use it only as a personal awareness check.