Body Surface Area Calculator For Burns

Rule of Nines Formula:

\[ \%TBSA = (Head\ 9\% + Each\ arm\ 9\% + Each\ leg\ 18\% + Front\ torso\ 18\% + Back\ torso\ 18\% + Genitals\ 1\%) \]

Head (%):

% (max 9)

Left Arm (%):

% (max 9)

Right Arm (%):

% (max 9)

Left Leg (%):

% (max 18)

Right Leg (%):

% (max 18)

Front Torso (%):

% (max 18)

Back Torso (%):

% (max 18)

Genitals (%):

% (max 1)

Total Body Surface Area (% TBSA):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Rule of Nines for Burns?

Definition: The Rule of Nines is a method used to estimate the total body surface area (TBSA) affected by burns.

Purpose: It helps medical professionals quickly assess burn severity and determine treatment needs, including fluid resuscitation.

2. How Does the Rule of Nines Work?

The body is divided into regions that represent 9% or multiples of 9% of the total body surface area:

\[ \%TBSA = (Head\ 9\% + Each\ arm\ 9\% + Each\ leg\ 18\% + Front\ torso\ 18\% + Back\ torso\ 18\% + Genitals\ 1\%) \]

Body Regions:

Head & Neck: 9% (front and back)
Each Arm: 9% (4.5% front, 4.5% back)
Each Leg: 18% (9% front, 9% back)
Torso Front: 18%
Torso Back: 18% (including buttocks)
Genitals: 1%

3. Importance of Burn Surface Area Calculation

Clinical Significance: Accurate TBSA estimation is crucial for:

Determining burn severity (minor, moderate, major)
Calculating fluid resuscitation needs (Parkland formula)
Assessing prognosis and mortality risk
Determining need for transfer to burn center

4. Using the Calculator

Instructions: Enter the percentage burned for each body region. The calculator sums these values to give total %TBSA burned.

Note: For partial burns to a region, estimate the percentage of that specific region affected (e.g., if half of one arm is burned, enter 4.5%).

5. Frequently Asked Questions (FAQ)

Q1: How does this differ for children?
A: Children have proportionally larger heads (up to 18%) and smaller legs. Use pediatric-specific charts for accurate assessment.

Q2: What about smaller burns?
A: For burns <10% TBSA, use the "palmar method" - patient's palm (including fingers) represents ~1% of their TBSA.

Q3: When is a burn considered major?
A: Generally burns >20% TBSA in adults or >10% in children, or burns involving critical areas (face, hands, feet, genitals).

Q4: How accurate is the Rule of Nines?
A: It provides quick estimation (±5-10%). For precise measurement, use Lund-Browder charts (more accurate for children).

Q5: What's the significance of %TBSA in treatment?
A: Fluid resuscitation formulas (e.g., Parkland) use %TBSA to calculate fluid requirements for the first 24 hours.