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Burn Surgery

Calculating burn size

Authors: Rami Mossad Ibrahim, MD, Elisabeth Lauritzen, MD, Frederik Gulmark Hansen med.stud., Magnus Balslev Avnstorp, MD and Rikke Holmgaard, Consultant, Burns Specialist, MD, PhD

When calculating the size of the burn in % of TBSA, only 2nd and 3rd degree burns are included (1). In adults, the Wallace rule of nines (fig. 1) may be applied to determine the total percentage of area burned for each major section of the body (2). 

The patient’s palm can serve as a reference point, roughly equivalent to 1% of TBSA. For children and infants, the Lund and Browder chart is used to assess the TBSA (3). In children, it is important to remember that the relative combined surface area of the head and neck compared to the surface area of the limbs is typically larger.

Figure 1 | Wallace rule of nines

Another feasible and easy way to estimate burn size is the Burn App. Burn App is an excellent tool to quickly estimate the size (%) of the burn area and to calculate the fluid resuscitation to be administered in the first 24 hours hours of treatment.

Link to www.Burn-App.com

Figure 2 | Screendumps from the Burn-App


  1. Rickard RF, Martin NAJ, Lundy JB. Imprecision in TBSA calculation. Burns [Internet]. 2014 Feb [cited 2018 Mar 25];40(1):172–3. Available from: http://www.ncbi.nlm.nih.gov/pubmed/24075539
  2. Tocco-Tussardi I, Presman B, Huss F. Want Correct Percentage of TBSA Burned? Let a Layman Do the Assessment. J Burn Care Res [Internet]. 2017 Aug 20 [cited 2018 Mar 25];39(2):1. Available from: http://www.ncbi.nlm.nih.gov/pubmed/28877135
  3. Taylor FH, Levenson SM, Davidson CS, Browder NC, Lund CC. PROBLEMS OF PROTEIN NUTRITION IN BURNED PATIENTS. Ann Surg [Internet]. 1943 Aug [cited 2018 Mar 25];118(2):215–20. Available from: http://www.ncbi.nlm.nih.gov/pubmed/17858259


Illustrations: Caroline Lilja, med.stud.