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MasterMath

Rule of Nines Burn Calculator

Total body surface area burned by the rule of nines, and fluid resuscitation by the Parkland formula. A child's percentages are not an adult's.

Body surface area burned

—

Body surface area burned—
Fluids in 24 h (Parkland)—
In the first 8 h—
Rate for the first 8 h—
Rate for the next 16 h—
Resuscitation threshold—

Contribution of each area

AreaWorthBurnedAdds

How this was worked out

    Indicative result. An extensive burn is a medical emergency. This calculation is the standard bedside tool, not a treatment guide and no substitute for immediate care.

    The formula

    Parkland: 4 ml × kg × % burned, half in the first 8 hours

    Where it comes from

    The rule of nines divides body surface into areas worth nine or a multiple of nine: each arm nine, each leg eighteen, the front of the torso eighteen and the back another eighteen, the head nine and the perineum one. In a child the proportions shift considerably: the head is worth eighteen and each leg fourteen, because a child's head is proportionally much larger. Using adult percentages on a child underestimates the burn exactly where it matters most.

    How to work it out by hand

    1. Identify which areas are burned and what fraction of each
    2. Multiply each area's percentage by the fraction burned
    3. Add all the contributions: that is the total surface burned
    4. Apply Parkland: 4 ml per kilo per percentage point over 24 hours

    What is worth knowing

    Parkland's eight hours run from the moment of the burn, not from arrival at hospital, and that is the classic mistake: if the patient arrived two hours later, half the volume has to go in over the six that remain. The formula is a starting point and gets adjusted against urine output. First-degree burns, red without blistering, do not count towards the percentage. The threshold for intravenous resuscitation is 20 % in an adult and 10 % in a child.

    Frequently asked questions

    Do I count first-degree burns?

    No. Red areas without blistering do not go into the percentage: only second degree and deeper count.

    Why do the percentages change in a child?

    Because their head is proportionally much larger and their legs smaller. Using adult figures underestimates the burn.

    When do the eight hours start?

    From the moment of the burn, not from arrival at hospital. It is the most repeated mistake with this formula.

    Is there a more precise method?

    Yes, the Lund and Browder chart, which adjusts by age area by area. The rule of nines is the fast one.

    Can I use the palm to estimate?

    As a quick reference, the patient's own palm with fingers is about 1 % of their body surface.