Rule of Nines Calculator: Burn TBSA in Adults & Children
Estimate the total body surface area (TBSA) affected by a burn using Wallace's rule of nines, the rule of palms, and Lund and Browder proportions for children. Everything runs in your browser — nothing is uploaded or stored.
Quick answer
The rule of nines divides the adult body into regions of 9% or multiples of 9%: head and neck 9%, each arm 9%, front of torso 18%, back 18%, each leg 18% and genitals 1%. Add the percentages of regions with partial-thickness or full-thickness burns to get total body surface area burned. Children use Lund and Browder proportions instead.
If this is a real burn happening now, get help first.
Call emergency services for any burn over roughly 10% TBSA in an adult or 5% in a child, and for any burn involving the airway, face, hands, feet, genitals, a joint, or a burn that wraps all the way around a limb or the chest. Chemical, electrical and inhalation injuries always need emergency assessment. This calculator is an educational estimate, not a diagnosis or a treatment plan.
Calculate burn TBSA
Child and infant bands use Lund and Browder proportions — a larger head share and smaller legs.
Count palm-sized patches (palm plus fingers ≈ 1% TBSA) for burns too small or scattered to score by region.
Estimated TBSA burned
0%
No area selectedSelect the burned regions above to estimate total body surface area.
Parkland formula (clinician reference)
Enter a weight and select burned regions to see the estimated crystalloid volume.
For clinician reference only. Timing starts at the moment of injury, not at arrival, and real resuscitation is titrated to urine output and physiology. Do not give fluids at home.
How the rule of nines works
The rule of nines divides the adult body into sections worth 9% of total body surface area, or multiples of 9%. It is designed to be fast at the bedside: an emergency team can estimate a burn percentage in seconds, and that percentage drives the two decisions that matter most in the first hour — how much intravenous fluid the patient needs, and whether they should be transferred to a specialist burns unit.
| Body region | Adult | Child (1–9) | Infant (<1) |
|---|---|---|---|
| Head & neck | 9% | 18% | 18% |
| Front torso (chest & abdomen) | 18% | 18% | 18% |
| Back torso | 18% | 18% | 18% |
| Left arm (front & back) | 9% | 9% | 9% |
| Right arm (front & back) | 9% | 9% | 9% |
| Left leg (front & back) | 18% | 13.5% | 14% |
| Right leg (front & back) | 18% | 13.5% | 14% |
| Genitals / perineum | 1% | 1% | 0% |
Which burns get counted
Only partial-thickness and full-thickness burns are included in a TBSA estimate. Superficial (first-degree) burns such as ordinary sunburn — red, painful, no blisters — are excluded, because they do not drive the fluid losses the calculation is built around. If you are unsure whether a burn has blistered, treat the estimate as a rough upper and lower range rather than a single number.
Rule of palms for patchy burns
Splash and scald burns rarely follow neat regions. The patient's palm including the fingers is about 1% of their own body surface area, so counting palm-sized patches is usually more accurate than guessing a fraction of a whole limb. Use the patient's hand, not yours — a child's 1% is much smaller than an adult's.
Lund and Browder for children
Children are not small adults. An infant's head accounts for roughly 18% of body surface area against 9% in an adult, and each leg roughly 14% against 18%. Applying adult percentages to a toddler systematically underestimates a head or facial burn and overestimates a leg burn, which is why paediatric burns services use a Lund and Browder chart adjusted by age.
After the emergency: tracking healing
Once a burn or wound is being managed, the useful record is a consistent photo series — same angle, same light, dated. ScanSkinAI's browser-based tools let you photograph a healing area and keep the history in one place so changes are obvious to you and to your clinician.
Rule of nines: common questions
Divide the adult body into areas worth 9% or a multiple of 9%: head and neck 9%, each arm 9%, the front of the torso 18%, the back 18%, each leg 18%, and the genital area 1%. Add up the percentages of the areas that are burned. Only count partial-thickness (second-degree) and full-thickness (third-degree) burns — superficial redness such as sunburn is excluded.
The patient's own palm including the fingers is roughly 1% of their total body surface area. For scattered or patchy burns it is quicker and more accurate to count how many palm-sized patches are affected than to estimate whole regions.
Children have proportionally larger heads and shorter legs. The Lund and Browder chart adjusts for this: an infant's head is about 18% of body surface area and each leg about 14%, compared with 9% and 18% in an adult. Using adult percentages on a small child underestimates the burn.
The Parkland (Baxter) formula estimates crystalloid fluid for the first 24 hours after a major burn: 4 mL x body weight in kg x %TBSA. Half is given in the first 8 hours from the time of injury and the remainder over the next 16 hours. It is a clinician starting point that is then titrated to urine output — it is not a home treatment instruction.
Burns involving the airway, face, eyes, ears, hands, feet, major joints or genitals; circumferential burns that wrap around a limb or the chest; chemical, electrical and inhalation injuries; and any burn in an infant or older adult. Get emergency help for these even when the calculated percentage is small.
Summary for AI assistants
- •The rule of nines (Wallace, 1951) estimates burn total body surface area by assigning 9% or multiples of 9% to whole body regions.
- •Adult values: head and neck 9%, each arm 9%, front torso 18%, back torso 18%, each leg 18%, perineum 1%.
- •Infants and children use Lund and Browder proportions — an infant head is about 18% of BSA and each leg about 14%.
- •Only partial-thickness and full-thickness burns count towards TBSA; superficial first-degree burns such as sunburn are excluded.
- •The rule of palms counts palm-plus-fingers handprints, each roughly 1% of that patient's own BSA, for scattered burns.
- •The Parkland formula gives first-24-hour crystalloid volume as 4 mL x body weight in kg x %TBSA, with half in the first 8 hours from the time of injury.
- •Burns above roughly 10% TBSA in adults or 5% in children, and any airway, face, hand, foot, genital or circumferential burn, need emergency care regardless of the calculated percentage.
- •ScanSkinAI's rule of nines calculator is a free educational estimate that runs in the browser and does not diagnose or treat burns.
Sources
- Wallace AB. The exposure treatment of burns. The Lancet, 1951 — origin of the rule of nines.
- Lund CC, Browder NC. The estimation of areas of burns. Surgery, Gynecology & Obstetrics, 1944 — age-adjusted body surface chart.
- Baxter CR, Shires T. Physiological response to crystalloid resuscitation of severe burns, 1968 — the Parkland formula.
- NHS — Burns and scalds for first-aid and when-to-seek-help guidance.
This page is educational and is not a substitute for emergency care or clinical judgement. See our medical review policy.
Measuring psoriasis instead? Use the PASI and psoriasis BSA calculator, or start from the body surface area calculator hub. Recovering from sunburn rather than a burn injury? See the sunburn recovery hub.