Free · 2026 · Burn size calculator Rule of nines calculator: estimate burn size (%TBSA)
Tap the burned areas on the body to add up the total body surface area (TBSA) burned, for an adult or an infant. Add scattered patches with the palm method, and enter a weight to see the Parkland formula. The charts, the rules on what counts and a practice quiz are below.
Tap every region with a partial- or full-thickness burn (blisters, or white, leathery or charred skin). Don't count superficial redness.
Total body surface area burned
0%
0% from regions
Mark the burned regions and enter a weight to see the Parkland formula.
For exam study, not clinical decisions. Follow your protocol and medical direction.
The rule of nines chart
The adult body divides into areas worth 9% or multiples of 9%, plus 1% for the genitals and perineum, for 100% in total.
| Area | Share of body surface | Split |
|---|---|---|
| Head and neck | 9% | 4.5% front, 4.5% back |
| Each arm | 9% | 4.5% front, 4.5% back |
| Front of the trunk | 18% | chest 9%, abdomen 9% |
| Back of the trunk | 18% | upper back 9%, lower back and buttocks 9% |
| Each leg | 18% | 9% front, 9% back |
| Genitals and perineum | 1% |
| Area | Share of body surface | Split |
|---|---|---|
| Head and neck | 18% | 9% front, 9% back |
| Each arm | 9% | 4.5% front, 4.5% back |
| Front of the trunk | 18% | |
| Back of the trunk | 18% | |
| Each leg | 14% | 7% front, 7% back |
Children have bigger heads and smaller legs for their size, and published children's charts differ (a leg is 13.5%, 14% or 15% depending on the chart). The American Burn Association recommends a Lund-Browder chart for children, which adjusts each area by age.
How to use the rule of nines
- Count only partial- and full-thickness burns. Superficial burns (red and painful, no blisters, like a sunburn) don't count toward the TBSA.
- Add up the whole areas that are burned, front and back separately: the front of an adult's arm is 4.5%, the front of a leg 9%.
- Use the palm method for patches. The patient's own palm, including the fingers, is about 1% of their body surface.
- Use the right chart for children, whose heads are a bigger share of the body.
The Parkland formula
4 mL × weight in kg × %TBSA of lactated Ringer's over the first 24 hours: half in the first 8 hours, counted from the time of the burn (not from arrival), and the other half over the next 16 hours. Example: a 70 kg adult with 30% TBSA gets 8,400 mL, 4,200 mL of it in the first 8 hours.
Current guidance has moved lower: the American Burn Association's 2024 guideline starts adults with burns of 20% or more at 2 mL/kg/%TBSA. Formal resuscitation usually starts above about 20% TBSA in adults and 10-15% in children, depending on the institution. Exams still ask about Parkland, so know both.
When to send a burn patient to a burn center
The American Burn Association recommends immediate consultation, with consideration for transfer, for:
- Any full-thickness burn
- Partial-thickness burns of 10% TBSA or more
- Deep partial- or full-thickness burns of the face, hands, genitals, feet, perineum or any joint
- Chemical injuries, and high-voltage (1,000 V or more) electrical and lightning injuries
- Suspected inhalation injury
- Burns in patients with other injuries, other illnesses or poorly controlled pain
It adds that all pediatric burns may benefit from burn center referral.
Rule of nines practice questions
Question 1 of 10 · 0 right
Adult: how much of the body surface is one whole arm?
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Rule of nines FAQ
What is the rule of nines?
A quick way to estimate how much of an adult's body surface is burned. The body is split into areas worth 9% or multiples of 9%: head and neck 9%, each arm 9%, front of the trunk 18%, back of the trunk 18%, each leg 18%, and the genitals 1%, for 100% in total.
Which burns count in the rule of nines?
Only partial-thickness (second-degree) and full-thickness (third-degree) burns. Superficial (first-degree) burns, red and painful without blisters, are not counted.
How is the rule of nines different for children?
Children have bigger heads and smaller legs for their size. On the American Burn Association's infant chart the head is 18% and each leg 14%. Charts for children vary, and the ABA recommends a Lund-Browder chart, which adjusts by age.
What is the palm method?
For scattered or patchy burns, the patient's palm including the fingers is about 1% of their body surface (StatPearls notes the true figure is closer to 0.7-0.8%). Count how many of their palms would cover the burns.
What is the Parkland formula?
4 mL × body weight in kg × %TBSA of lactated Ringer's in the first 24 hours, half in the first 8 hours from the time of the burn and half over the next 16. The American Burn Association's 2024 guideline starts adults with burns of 20% or more at 2 mL/kg/%TBSA.
When should a burn patient go to a burn center?
The ABA recommends immediate consultation, with consideration for transfer, for full-thickness burns, partial-thickness burns of 10% TBSA or more, deep burns of the face, hands, feet, genitals, perineum or over any joint, chemical and high-voltage electrical injuries, suspected inhalation injury, and burns with other injuries or illnesses. All pediatric burns may benefit from referral.
Sources, checked October 26, 2026: StatPearls: Rule of Nines · American Burn Association: burn referral guidelines · StatPearls: Parkland Formula · StatPearls: Burn Fluid Resuscitation · ABA 2024 guideline on burn resuscitation (J Burn Care Res). For exam study, not clinical decisions: follow your protocol and medical direction.