PHQ-9 Depression Calculator

PHQ-9 Depression Calculator for Psychiatry. Use the score to open a clinical discussion, not select medication automatically. Self-harm concerns require direct assessment whatever the total; NICE advises against using risk scales to predict suicide or decide discharge.

For shared guidance on choosing a tool and documenting results, read the clinical calculator workflow.

How this calculator works

This is total-score entry, not questionnaire administration. Published symptom-severity bands begin at 5, 10, 15 and 20; these are not diagnoses. See the original validation: https://pubmed.ncbi.nlm.nih.gov/11556941/.

When to use this calculator

Review a completed assessment and discuss symptom burden and functional change. The original item responses still matter; a total cannot show which concerns were endorsed.

Inputs used

  • Completed PHQ-9 integer total, 0-27
  • Version and assessment context from the original form

Clinical interpretation

Use the score to open a clinical discussion, not select medication automatically. Self-harm concerns require direct assessment whatever the total; NICE advises against using risk scales to predict suicide or decide discharge.

Worked example

A finalized score of 12 falls in the moderate symptom range. A later 7 is five points lower, in the mild range. The arithmetic decrease is 5/12 x 100 = 41.7%, but that is not a 41.7% reduction in suicide risk or proof of recovery.

Limitations and safety notes

Missing answers are not zero. Language, setting and clinical context affect interpretation. No original questions, response choices, diagnostic interview or treatment algorithm is provided.

Frequently asked questions

Can a low total establish safety?

No. The total does not reveal all safety concerns and is not a suicide-risk assessment.

References

  • Kroenke et al., 2001, primary validation. https://pubmed.ncbi.nlm.nih.gov/11556941/
  • NICE NG225, risk assessment limits. https://www.nice.org.uk/guidance/ng225/chapter/recommendations

Editorial review and citation methodology

Maintained by the Quick Medical Calculator Editorial Team. Content record date: September 9, 2026. A content date is not evidence of independent clinical review. Individual clinical sign-off is not recorded on this page.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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