Your estimated total body surface area (TBSA) burned determines the severity classification and initial management approach. Burns affecting less than 10% TBSA in adults can typically be managed with oral hydration and outpatient wound care. Burns affecting 10-20% TBSA usually require intravenous fluid resuscitation using the Parkland formula (4 mL x body weight in kg x %TBSA, with half given in the first 8 hours and the remainder over the next 16 hours). Burns exceeding 20% TBSA represent a major burn requiring burn center care, aggressive fluid resuscitation, and multidisciplinary management.

The TBSA percentage also guides decisions about burn center referral, nutritional support requirements, and the risk of systemic complications including burn shock, acute kidney injury, and infection. Higher TBSA burns carry significantly increased mortality, particularly when combined with inhalation injury or advanced patient age.

Use the Rule of Nines for rapid initial assessment of burn extent in adult patients in emergency and acute care settings. It is designed for quick field or bedside estimation when immediate decisions about fluid resuscitation, triage, and transfer are needed. It is the standard initial burn assessment tool used by emergency physicians, surgeons, and paramedics.

This tool is most appropriate for adults. For children, the Lund-Browder chart provides more accurate TBSA estimation because body proportions differ significantly from adults (children have proportionally larger heads and smaller legs). For small or scattered burns, the patient's palm (including fingers) represents approximately 1% TBSA and can be used for more precise estimation.

The Rule of Nines provides an approximation and tends to overestimate burn size compared to more precise methods like the Lund-Browder chart. It is designed for adults and is inaccurate for children and infants, who have proportionally larger heads (approximately 18% at birth versus 9% in adults) and smaller legs. Obese patients also have altered body proportions that the standard Rule of Nines does not account for.

The tool does not assess burn depth (superficial, partial-thickness, or full-thickness), which is critical for treatment planning and prognosis. It also does not capture the severity of associated injuries such as inhalation injury, which independently doubles mortality. Accurate TBSA estimation requires that only second-degree (partial-thickness) and third-degree (full-thickness) burns be counted — first-degree burns (erythema only, like sunburn) should be excluded from the calculation.