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Pediatric Weight Estimation by Age (APLS)

APLS (6th edition) age-based weight estimates for resuscitation: 0–12 months (0.5 × age in months) + 4 kg; 1–5 years (2 × age) + 8 kg; 6–12 years (3 × age) + 7 kg. Use a measured weight or length-based tape when available.

Age (years or months)

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Interpretation

Result	Meaning
0–12 months	(0.5 × age in months) + 4
1–5 years	(2 × age in years) + 8
6–12 years	(3 × age in years) + 7

Formula

0–12 mo: W = 0.5 × months + 4 · 1–5 y: W = 2 × years + 8 · 6–12 y: W = 3 × years + 7 (age in completed months/years)

Clinical pearls

Age formulas are a fallback: a measured weight, parental report or length-based tape (Broselow) is preferred.
Formulas tend to underestimate weight in obese children and overestimate in malnourished children; not for adolescents ≥ 13 years.
The older APLS formula 2 × (age + 4) underestimated weight by ~33% in a modern UK cohort.

Examples

apls weight 3 year old estimated weight for a 6 month old how much does an 8 yo weigh, resus estimate

FAQ

How do you estimate a child's weight from age?

Under 1 year: half the age in months plus 4 kg. Age 1–5: twice the age plus 8. Age 6–12: three times the age plus 7.

How much does a 3-year-old weigh for resuscitation?

APLS estimate is (2 × 3) + 8 = 14 kg.

Evidence

Luscombe MD, Owens BD, Burke D. Weight estimation in paediatrics: a comparison of the APLS formula and the formula "Weight=3(age)+7". Emerg Med J 2011;28:590–3.

Pediatrics & Obstetrics · Reviewed 2026-10-14 · Methodology