Burned Body Surface Area Calculator
Calculate the percentage of burned body area using Wallace's Rule of Nines to assess burn severity and guide treatment.
Important Medical Disclaimer
This calculator is an educational and clinical decision support tool. Results DO NOT replace professional medical evaluation, laboratory tests, or clinical judgment. Always consult a qualified healthcare professional for diagnosis, treatment, and clinical decisions. Calculations are based on scientifically validated formulas but may not be applicable to all patients.
Select burned areas
What is the Rule of Nines?
Developed by Wallace in 1951, the Rule of Nines divides the adult body into areas representing 9% or multiples of 9% of total body surface. Head=9%, each arm=9%, anterior trunk=18%, posterior trunk=18%, each leg=18%, genitalia=1%, totaling 100%. It is a rapid method to estimate burn extent and calculate fluid resuscitation. In children, use Lund-Browder chart (proportionally larger head).
When to use the Rule of Nines?
Use in all initial major burn assessments. Essential to classify severity, decide admission, and calculate fluid resuscitation (Parkland formula: 4mL x weight(kg) x %TBSA in first 24h, half in first 8h). Burns >20% in adults or >10% in children/elderly require IV fluid resuscitation. >40% has significant mortality. Reassess periodically.
Limitations and Considerations
Rule of Nines is less accurate in children (use Lund-Browder). Does not consider depth (1st, 2nd, 3rd degree). Only 2nd and 3rd degree burns are counted for TBSA. Patient's palm ≈ 1% TBSA (useful for irregular burns). Smoke inhalation, circumferential and electrical burns worsen prognosis regardless of TBSA. Always assess depth and location.
Frequently Asked Questions about Burn Area
How to calculate fluid resuscitation in burns?
Use Parkland formula: 4mL x weight(kg) x %TBSA = total volume of Lactated Ringer in first 24h. Half in first 8h (from time of burn, not admission), half in remaining 16h. Example: 70kg, 30% TBSA = 8,400mL (4,200mL in 8h, 4,200mL in 16h). Adjust by urine output (goal 0.5-1mL/kg/h).
Are 1st degree burns counted?
No. Only 2nd degree (partial thickness, with blisters) and 3rd degree (full thickness, painless, white/charred) burns are included in TBSA calculation. 1st degree burns (erythema, no blisters) do not require fluid resuscitation and are not included in calculation.
When to transfer to burn center?
Transfer criteria: >20% TBSA in adults, >10% in children/elderly, 3rd degree burn >5%, burn on face/hands/feet/genitalia/perineum/joints, electrical burn, smoke inhalation, chemical burn, burn + trauma, severe comorbidities, circumferential burn of chest/limbs.
What is escharotomy and when is it needed?
Escharotomy is incision in eschar (3rd degree burned tissue) to relieve compartment syndrome. Needed in circumferential 3rd degree burns on limbs (vascular compression, ischemia) or chest (ventilatory restriction). It is an emergency bedside procedure. Not to be confused with fasciotomy (deeper).