Use this independent UK calculator to estimate an adult Malnutrition Universal Screening Tool (MUST) score from BMI, unplanned weight loss and the acute disease effect. It follows the published BAPEN scoring thresholds and is intended to support understanding, not replace trained clinical assessment or local policy.
MUST score calculator
Adults only. Enter measured values where possible.
Your screening result
BMI: kg/m² — score
Unplanned weight loss: % — score
Acute disease effect score:
Total MUST score:
Risk category:
What is the MUST calculator?
MUST stands for Malnutrition Universal Screening Tool. BAPEN developed the five-step screening method for adults. NICE lists MUST as an example of a validated tool that can be used when screening for malnutrition risk. It is used across hospital, community and care settings.
How the MUST score is calculated
The score combines three components. BMI above 20 scores 0, BMI from 18.5 to 20 scores 1, and BMI below 18.5 scores 2. Unplanned weight loss below 5% scores 0, 5–10% scores 1, and more than 10% scores 2. The acute disease effect adds 2 points when the person is acutely ill and there has been, or is likely to be, no nutritional intake for more than 5 days.
Understanding the result
| Total score | Risk category | Meaning |
|---|---|---|
| 0 | Low | Routine clinical care and setting-appropriate repeat screening. |
| 1 | Medium | Observe and review nutritional intake according to local policy. |
| 2 or more | High | Clinical/dietetic action is generally required under the relevant care pathway. |
Worked example
An adult who is 170 cm tall and currently weighs 60 kg has a BMI of about 20.8, giving a BMI score of 0. If they weighed 66 kg several months ago and the loss was unplanned, the loss is about 9.1%, giving a weight-loss score of 1. With no acute disease effect, the total score is 1, which is the medium-risk category.
Important limitations
This simplified calculator requires measured height and weight. The full BAPEN toolkit includes alternative procedures where measurements are unavailable and requires extra care in some circumstances, including fluid disturbance, amputations, critical illness, pregnancy and lactation. MUST is for adults and is a screening tool, not a diagnosis. Healthcare professionals should follow the full BAPEN guidance and their local clinical policy.
NICE and nutritional screening
NICE recommends that screening considers BMI, percentage unintentional weight loss and reduced or potentially impaired nutrient intake. NICE also says malnutrition screening should be carried out by healthcare professionals with appropriate skills and training.
Related calculators
Related tools include the NHS Calculator hub, MUAC Calculator NHS, NEWS2 Calculator NHS, Anticholinergic Burden Calculator NHS, Oxford Knee Score Calculator NHS, TDEE Calculator NHS and Calorie Deficit Calculator NHS.
Authoritative sources
- BAPEN — official MUST calculator
- BAPEN — MUST and self-screening resources
- NICE CG32 — Nutrition support for adults
Frequently asked questions
What does a MUST score of 0 mean?
A total score of 0 is the low-risk category. Repeat screening should still follow the schedule and policy for the care setting.
What does a MUST score of 1 mean?
A score of 1 is the medium-risk category and normally prompts observation and review according to local nutritional care policy.
What does a MUST score of 2 or more mean?
A score of 2 or more is the high-risk category and should lead to appropriate clinical or dietetic action under the applicable care pathway.
Is MUST suitable for children?
No. The BAPEN MUST tool is designed for adults.
Disclaimer
This is an independent educational implementation based on published MUST scoring thresholds. It is not the official BAPEN calculator and this website is not operated, approved or endorsed by BAPEN or the NHS. Do not use it as a substitute for professional assessment, the full MUST toolkit or local clinical policy.