Trauma & Burns

Burn Size (Rule of Nines) Calculator

Total body surface area burned from the regions involved.

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Turn on JavaScript to use this calculator, or open it in the web app.

Formula

Adult: head 9, each arm 9, front trunk 18, back trunk 18, each leg 18, genitals 1
Child: head 18, each arm 9, front trunk 18, back trunk 18, each leg 14

How it is used

• Count only partial- and full-thickness (second- and third-degree) burns; superficial redness is excluded.
• For scattered burns, the patient’s own palm and fingers equal about 1% of body surface area.
• Use the percentage in the burn fluid calculator and to decide on burn center transport.

Same formula as the app. Open it in the web app.

Related one-pagers

• BurnsRule of nines. Count partial and full thickness only, not red unblistered skin.
• Trauma: Primary and Secondary Survey

Related calculators

• Burn Fluids (ABA Consensus 2 mL/kg)
• Canadian CT Head Rule (CCHR)
• NEXUS Cervical Spine Criteria (NEXUS)
• Ottawa Ankle and Foot Rules
• Ottawa Knee Rule

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your institution’s protocols. Not a substitute for clinical judgment.