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Malnutrition Risk (MUST) Calculator

Work out malnutrition risk (must) instantly with clear inputs, formula shown and shareable results.

About Malnutrition Risk (MUST) Calculator

Scores the three MUST steps — body mass index, unplanned weight loss and acute disease effect — and gives the corresponding care pathway.

Formula

MUST

BMI >20 = 0, 18.5-20 = 1, <18.5 = 2; weight loss <5% = 0, 5-10% = 1, >10% = 2; acute disease with no intake for over 5 days = 2. Total 0 low, 1 medium, 2 or more high risk

Worked example

With the default values below, Malnutrition Risk (MUST) Calculator returns MUST total of 3. Change any input above and every figure here is recalculated in your browser.

Inputs used

Body mass indexaccepts 10–60 kg/m2
18 kg/m2
Unplanned weight loss in 3 to 6 monthsaccepts 0–40 %
6 %
Acutely ill with no nutritional intake for over 5 daysone of Yes (2 points), No
No

Results

MUST total
3
Risk band and action
High risk — refer to dietetics and start nutritional support
Points from BMI
2
Points from weight loss
1

Step by step

  1. 1Values used
  2. 2MUST
  3. 3MUST total= 3
  4. 4Risk band and action= High risk — refer to dietetics and start nutritional support
  5. 5Points from BMI= 2
  6. 6Points from weight loss= 1

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

What if height cannot be measured?

MUST allows surrogate measures such as ulna length or mid-upper arm circumference.

How often should MUST be repeated?

Weekly for hospital inpatients and monthly in care homes is the usual standard.

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