Rule of Nines Calculator
Estimate Total Body Surface Area (TBSA) burned using Wallace's Rule of Nines. Select the burn coverage for each body region — Parkland fluid resuscitation volumes calculate automatically.
Select the percentage of each body region affected by 2nd or 3rd degree burns only. Superficial (1st degree) burns are not counted.
Enter patient weight to auto-calculate Parkland IV fluid volumes.
Calculation Results
Formula Used
💡 Timing: Give ½ in the first 8 hours from time of injury; ½ over the next 16 hours. Use Lactated Ringer's (LR) — not normal saline.
Terms Used
— Patient weight (kg or lbs): used only for Parkland fluid volume calculation.
— Burn Severity: Minor (<10%), Moderate (10–20%), Major (20–40%), Critical (>40%).
— Parkland 24h Volume (mL LR): total IV fluid for first 24 hours post-injury.
— 8h / 16h split: first half given within 8h of injury; second half over next 16h.
What is the Rule of Nines?
Origin & Clinical Significance
The Rule of Nines, formally known as Wallace's Rule of Nines after Scottish surgeon Alexander Burns Wallace who popularized it in 1951, is a rapid, standardized anatomical estimation tool used in emergency medicine, trauma surgery, and nursing practice to calculate the percentage of Total Body Surface Area (TBSA) affected by burns. The extent and depth of a burn are the two primary determinants of patient prognosis, fluid resuscitation requirements, and the need for transfer to a specialist burn center.
The human body is divided into anatomical regions, each assigned a value of approximately 9% (or a multiple thereof) of the total body surface area, with the perineum accounting for the remaining 1% to reach 100%. Only partial-thickness (second-degree) and full-thickness (third-degree) burns are included in TBSA calculations. Superficial (first-degree) burns are excluded because they do not cause significant fluid shifts and heal within 3–5 days without scarring.
Anatomical Region Breakdown
Head & Neck (9%): Anterior face/scalp = 4.5%; posterior head/neck = 4.5%.
Each Arm (9% each = 18% total): Anterior surface = 4.5%; posterior surface = 4.5%.
Anterior Trunk (18%): Anterior chest = 9%; anterior abdomen = 9%.
Posterior Trunk (18%): Upper back = 9%; lower back + buttocks = 9%.
Each Leg (18% each = 36% total): Thigh = 9%; lower leg + foot = 9%.
Perineum / Genitalia (1%).
Total: 9 + 18 + 18 + 18 + 36 + 1 = 100%. For scattered burns, the Rule of Palms (patient's palm ≈ 1% TBSA) supplements estimation.
Parkland Formula & Fluid Protocol
Use Lactated Ringer's (LR) solution — half in the first 8 hours, half over the next 16 hours, both timed from the moment of injury, not hospital arrival. Target urine output: 0.5 mL/kg/h for adults, 1 mL/kg/h for children.
The Parkland formula was developed by Charles Baxter at Parkland Memorial Hospital in Dallas in the 1960s and remains the international standard for burn resuscitation. It was later endorsed by the American Burn Association. Clinicians may adjust volumes hourly based on urine output, avoiding both under-resuscitation (organ failure) and over-resuscitation (abdominal compartment syndrome, pulmonary edema).
5 Clinical Worked Examples
Example 1: Kitchen Scald — 27% TBSA
- Burns: Full anterior torso (18%) + full right arm (9%) = 27% TBSA
- Parkland (75 kg): 4 × 75 × 27 = 8,100 mL. First 8h = 4,050 mL (506 mL/h); Next 16h = 4,050 mL (253 mL/h).
- Action: Burn unit admission. Target urine ≥ 37 mL/h. Start LR immediately.
Example 2: House Fire — Delayed Arrival (2h post-injury)
- Burns: Full posterior torso (18%) + full head/face (9%) = 27% TBSA. Patient arrives 2h post-injury.
- Parkland (60 kg): 4 × 60 × 27 = 6,480 mL. First-half (3,240 mL) must infuse in remaining 6h = 540 mL/h. Then 3,240 mL over 16h = 203 mL/h.
- NCLEX Key Point: Always time from INJURY, not arrival.
Example 3: Chemical Burn — Legs & Genitalia
- Burns: Full right leg (18%) + genitalia (1%) = 19% TBSA
- Parkland (80 kg): 4 × 80 × 19 = 6,080 mL. First 8h = 3,040 mL; Next 16h = 3,040 mL.
- Note: Perineal burns = high infection risk, mandatory catheterization. Acid burns — irrigate copiously with water for 20–30 min before dressing.
Example 4: Electrical Burn — Myoglobinuria Risk
- Burns: Right arm anterior (4.5%) + anterior torso partial (9%) = 13.5% TBSA
- Special Action: Electrical burns require higher volumes. If urine is dark/myoglobinuric, increase target to 75–100 mL/h until urine clears. May require sodium bicarbonate to alkalinize urine and prevent acute tubular necrosis.
Example 5: Minor Burn — Outpatient Management
- Burns: Right arm anterior surface only = 4.5% TBSA
- Management: Below 15% TBSA in a healthy adult — IV resuscitation typically NOT required. Outpatient wound care, oral fluids, tetanus prophylaxis, follow-up in 24–48h.
Clinical Limitations & Special Situations
1. Not Accurate for Children: Use the Lund-Browder Chart for patients under 15 years. Infants have proportionally larger heads and smaller legs.
2. Inhalation Injury: Patients with inhalation injury (hoarse voice, singed nasal hairs, carbonaceous sputum) require up to 1.5–2× the calculated Parkland volume. Early intubation may be needed before progressive airway edema develops.
3. Burn Depth Changes: Burns may deepen 48–72 hours post-injury due to progressive dermal ischemia. Reassess TBSA after 48–72 hours.
4. Obese Patients: Standard TBSA percentages may be inaccurate in morbidly obese patients. Ideal body weight (IBW) is recommended for Parkland fluid calculation to avoid over-resuscitation.
5. The Rule of Palms: For scattered or irregular burns, the patient's palm with closed fingers ≈ 1% TBSA. Combine with the Rule of Nines for complex burn patterns.
Frequently Asked Questions
What is the Rule of Nines?
The Rule of Nines (Wallace's Rule of Nines) rapidly estimates TBSA burned by dividing the adult body into anatomical regions each representing 9% (or multiples), with the perineum at 1%.
What burns are excluded from TBSA calculation?
Superficial (first-degree) burns are excluded. Only 2nd and 3rd degree burns are counted. First-degree burns heal in 3–5 days without systemic fluid shifts.
How is the Parkland formula related to the Rule of Nines?
Parkland uses TBSA from Rule of Nines: 4 mL × Weight (kg) × %TBSA. Half given in first 8h, half over 16h, both timed from the moment of injury.
Is the Rule of Nines accurate for children?
No. Children have proportionally larger heads and smaller legs. Use the Lund-Browder Chart for patients under 15 years.
When does the 24-hour Parkland timeline start?
From the TIME OF INJURY, not hospital arrival. A patient arriving 4 hours post-injury must receive the first-half volume in the remaining 4 hours.
What is the target urine output during burn resuscitation?
0.5 mL/kg/hour for adults (≈30–50 mL/h for a 70 kg adult) and 1 mL/kg/hour for children. Hourly urinary catheter monitoring is mandatory for all major burns.
What fluid is used in the Parkland formula?
Lactated Ringer's solution (LR). LR mimics extracellular fluid and is preferred over normal saline to avoid hyperchloremic metabolic acidosis from high-volume crystalloid infusion.
What TBSA percentage requires IV fluid resuscitation?
Burns exceeding 15–20% TBSA in adults generally require IV fluid resuscitation with the Parkland formula. Below this threshold, oral hydration and outpatient wound care may be sufficient.
This calculator is for educational and clinical reference purposes only. Burn assessment and fluid resuscitation must be performed by licensed healthcare professionals. Clinical judgment and institutional protocols always supersede any calculator output.