How do I calculate burn area?

By the rule of nines: the body is divided into zones that are multiples of 9% (head 9%, arm 9%, trunk front and back 18% each, leg 18%, groin 1%). Select the burned regions — the calculator sums the percentages with age adjustment.

What is the palm rule?

For small burns the patient’s palm (with fingers) is taken as ≈ 1% of their body surface. It’s handy for quickly estimating scattered areas.

At what burn area is an ambulance needed?

Call an ambulance immediately for areas over 15–20% in adults and over 10% in children, and for burns of the face, hands, groin or airway and deep burns — regardless of area.

What is the Parkland formula?

It’s the fluid estimate for extensive burns: 4 mL × weight (kg) × %TBSA in the first 24 hours, half in the first 8. Therapy is given by a medical team; the calculator is only a guide.

How does burn area differ in children?

In children the head is relatively larger (up to 18% vs 9% in adults) and the legs smaller. So the adult rule of nines underestimates the area for a child; the calculator accounts for age.

Burn area: rule of nines calculator

The burn area determines its severity and fluid needs. Select the burned body regions and age — the calculator estimates the percentage of body surface (%TBSA) by the rule of nines and, from weight, computes fluid volume by the Parkland formula. It’s a first-aid guide, not a substitute for emergency care.

Estimate burn area

Rule of nines (% body surface)

In children the head is relatively larger and the legs smaller than in adults (simplified Lund-Browder). For small burns use the palm method: the patient’s palm ≈ 1%.

Region	Adults / Children
Head and neck	9% / 18%
Arm (each)	9% / 9%
Chest and abdomen	18% / 18%
Back	18% / 18%
Leg (each)	18% / 14%
Groin	1% / 1%

What burn area is and the rule of nines

Burn area is measured as a percentage of body surface (%TBSA). The “rule of nines” divides the body into zones that are multiples of 9%: head 9%, each arm 9%, the front and back of the trunk 18% each, each leg 18%, groin 1%.

The larger the area, the more severe the burn and the more important fluid replacement is. Only second- and third-degree burns (blisters and deeper) count; superficial redness (first degree) does not.

Age adjustment and the palm method

Children have different proportions: the head is relatively larger and the legs smaller. The calculator accounts for this if you choose “child” (simplified Lund-Browder).

For small scattered burns the palm method is handier: the patient’s palm (including fingers) is about 1% of their body surface.

When to call an ambulance and the Parkland formula

Call an ambulance immediately for a large area (over 15–20% in adults, over 10% in children), burns of the face, neck, hands, groin or airway, and for deep (third-degree) burns.

Extensive burns need fluid therapy. The Parkland formula: 4 mL × weight (kg) × %TBSA over the first 24 hours, half in the first 8 hours. This is done by a medical team; the calculator only shows the volume guide.

Frequently asked questions

By the rule of nines: the body is divided into zones that are multiples of 9% (head 9%, arm 9%, trunk front and back 18% each, leg 18%, groin 1%). Select the burned regions — the calculator sums the percentages with age adjustment.
For small burns the patient’s palm (with fingers) is taken as ≈ 1% of their body surface. It’s handy for quickly estimating scattered areas.
Call an ambulance immediately for areas over 15–20% in adults and over 10% in children, and for burns of the face, hands, groin or airway and deep burns — regardless of area.
It’s the fluid estimate for extensive burns: 4 mL × weight (kg) × %TBSA in the first 24 hours, half in the first 8. Therapy is given by a medical team; the calculator is only a guide.
In children the head is relatively larger (up to 18% vs 9% in adults) and the legs smaller. So the adult rule of nines underestimates the area for a child; the calculator accounts for age.

Questions about your health?

Describe the situation to the AI assistant — it suggests what to watch for and which doctor to see. For a severe burn, call an ambulance right away.

Ask AI

This calculator is for reference and information only and is not medical care. For burns of the face, airway, a large area or deep burns, call an ambulance immediately.