MUAC Calculator (Mid-Upper Arm Circumference Malnutrition Check)
Classify acute malnutrition in children aged 6–59 months from mid-upper arm circumference (MUAC) and edema using the WHO/UNICEF cutoffs: severe (SAM), moderate (MAM) or normal.
How it works
SAM: MUAC < 115 mm or bilateral pitting edema · MAM: 115 mm ≤ MUAC < 125 mm · no acute malnutrition: MUAC ≥ 125 mm (children 6–59 months)
Mid-upper arm circumference is measured on the left arm, halfway between the tip of the shoulder and the elbow, with the arm hanging relaxed. The WHO and UNICEF (2009) use MUAC below 115 mm, or pitting edema of both feet, to identify severe acute malnutrition in children aged 6–59 months, and 115–124 mm for moderate acute malnutrition. MUAC is quick, needs only a colored tape and predicts the risk of death well, so community health workers use it for screening; the diagnosis is completed with weight-for-height and a clinical examination.
Worked example
An 18-month-old child with a MUAC of 120 mm and no edema: 120 mm is between 115 and 124 mm (yellow zone), so the status is Moderate acute malnutrition (MAM) — 5 mm below the 125 mm cutoff; refer to a supplementary feeding program and follow up.
Sources: WHO & UNICEF (2009) WHO child growth standards and the identification of severe acute malnutrition in infants and children · WHO (2023) Guideline on the prevention and management of wasting and nutritional oedema in infants and children under 5 years
Frequently asked questions
How do you measure MUAC correctly?
Find the midpoint between the shoulder tip (acromion) and the elbow (olecranon) with the arm bent at 90°, mark it, then let the arm hang loose and wrap the tape around the mark without squeezing the skin. Read to the nearest millimeter.
What MUAC means severe malnutrition?
In children 6–59 months, a MUAC below 115 mm (red zone) or swelling of both feet means severe acute malnutrition, which needs urgent treatment, often with ready-to-use therapeutic food.
Can MUAC be used for babies under 6 months?
These cutoffs are validated only for 6–59 months. For infants under 6 months, health workers use weight-for-length, feeding problems and clinical signs, though newer research suggests MUAC around 110 mm may help.
Is a green MUAC always healthy?
A green MUAC (125 mm or more) rules out acute malnutrition by this measure, but a child can still be stunted, overweight or lacking micronutrients. Regular growth monitoring of weight and height is still needed.
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This calculator gives general guidance and is not a diagnosis or medical advice. If you are worried about your child, or they seem unwell, contact your pediatrician, a health center or emergency services.