MEWS Calculator (Modified Early Warning Score, Subbe 2001)

Understanding the MEWS calculator — concept and principle

The Modified Early Warning Score (MEWS) turns five routine bedside observations into points to help nurses and doctors spot patients on a general ward who are getting sicker. A rising score prompts closer monitoring or a call to a senior doctor or rapid response team.

Five vital signs, five scores: with the default inputs the result is MEWS 7 (higher risk).

How it is calculated

MEWS (0–14) = points for blood pressure + heart rate + breathing rate + temperature + consciousness

Systolic BP: 70 or less 3, 71–80 2, 81–100 1, 101–199 0, 200 or more 2.
Heart rate: 40 or less 2, 41–50 1, 51–100 0, 101–110 1, 111–129 2, 130 or more 3.
Respiratory rate: below 9 2, 9–14 0, 15–20 1, 21–29 2, 30 or more 3.
Temperature: below 35 °C 2, 35–38.4 °C 0, 38.5 °C or more 2.
Consciousness (AVPU): alert 0, voice 1, pain 2, unresponsive 3.

The principle

Before a cardiac arrest or ICU admission, most patients show hours of abnormal vital signs. Each observation is scored by how far it lies from normal, so several mild changes add up to a warning even when no single value looks alarming. Subbe and colleagues (2001) found in medical admissions that a score of 5 or more was linked with a higher risk of death (odds ratio 5.4) and of intensive care admission.

Worked example

Default inputs: systolic 96, heart rate 112, breathing rate 22, temperature 38.6 °C, alert.

Systolic 96 is in 81–100 → 1.
Heart rate 112 is in 111–129 → 2.
Breathing rate 22 is in 21–29 → 2.
Temperature 38.6 ≥ 38.5 → 2; alert → 0.
MEWS = 1 + 2 + 2 + 2 + 0 = 7 → Yes: higher risk.

Each point is the calculator re-run with only “Systolic blood pressure (mmHg)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Systolic blood pressure (mmHg)	MEWS (0–14)
24	9
48	9
72	8
96	7
120	6
144	6
192	6

How to read the result

Where does your result fall?

Hospitals set their own trigger levels and response plans; 5 or more is a common threshold for urgent review. Many UK and other hospitals now use NEWS2, which adds oxygen saturation and supplemental oxygen. Trends matter: a score that keeps rising needs action even below the trigger.

Common mistakes

Counting breaths for 15 seconds and multiplying, which is inaccurate; count a full minute.
Forgetting that a high blood pressure (200 or more) also scores.
Waiting for the trigger when the patient looks unwell.

Keep in mind: MEWS supports clinical judgement; it is not a diagnosis. Follow your hospital's escalation policy.

Frequently asked questions

What MEWS score is concerning?

A score of 5 or more was linked with higher risk in the original study, and many hospitals escalate at that level.

What is the difference between MEWS and NEWS2?

NEWS2 adds oxygen saturation and oxygen use, and is the national standard in the UK.

Can a normal MEWS miss a sick patient?

Yes. Pain, bleeding or other signs may not show in vital signs, so concern from staff or family should still be acted on.

Sources: Subbe CP, Kruger M, Rutherford P, Gemmel L, "Validation of a modified Early Warning Score in medical admissions", QJM 2001;94(10):521–526

Checked 9 Nov 2026. Subbe CP, Kruger M, Rutherford P, Gemmel L, “Validation of a modified Early Warning Score in medical admissions”, QJM 2001;94(10):521–526 (Table 1 and results).

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