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Acne Severity Grade Calculator

Work out acne severity grade instantly with clear inputs, formula shown and shareable results.

About Acne Severity Grade Calculator

Grades acne from lesion counts using the conventional four-grade scheme, where any nodules raise the grade and drive scarring risk.

Formula

Lesion count grading

Grade 1 comedonal; grade 2 15-50 inflammatory lesions; grade 3 nodules present; grade 4 more than 5 nodules, over 100 comedones or over 50 inflammatory lesions

Worked example

With the default values below, Acne Severity Grade Calculator returns Severity grade of Grade 3 — moderately severe acne with nodules. Change any input above and every figure here is recalculated in your browser.

Inputs used

Non-inflammatory lesionsaccepts 0–300
25
Inflammatory papules and pustulesaccepts 0–200
12
Nodules or cystsaccepts 0–50
1

Results

Severity grade
Grade 3 — moderately severe acne with nodules
Total lesion count
38
Inflammatory lesion count
13
Scarring note
Nodular lesions carry a higher scarring risk

Step by step

  1. 1Values used
  2. 2Lesion count grading
  3. 3Severity grade= Grade 3 — moderately severe acne with nodules
  4. 4Total lesion count= 38
  5. 5Inflammatory lesion count= 13
  6. 6Scarring note= Nodular lesions carry a higher scarring risk

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Why do nodules matter so much?

Nodular and cystic lesions cause permanent scarring, which is why they push treatment towards systemic therapy.

Are lesion counts reproducible?

Only moderately between observers, which is why global assessment scales are also used in practice.

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Acne Severity Grade Calculator – Calculate Severity grade