How do you calculate the Parkland formula?
Multiply 4 mL by the weight in kg and by the %TBSA burned. Half is given in the first 8 hours and half over the next 16. After a large burn, fluid leaks out of the circulation into the tissues for many hours; the Parkland formula, described by Baxter and Shires, gives a first estimate of the crystalloid needed over the first day.
Total for the first 24 h (mL) = 4 mL × weight (kg) × %TBSA
Both periods are counted from the time of the burn:
First 8 h: half the total → rate = total ÷ 2 ÷ 8
Next 16 h: the other half → rate = total ÷ 2 ÷ 16
How to use the calculator
- Enter the Weight in kg.
- Enter the Burned area (TBSA) in percent, counting only partial- and full-thickness burns. The value cannot exceed 100%.
- Read the Total in first 24 h, then the Rate, first 8 h, the Rate, next 16 h and the Volume in first 8 h.
- Rates are rounded to whole mL/h; the working shows them to one decimal place.
Worked examples
Example 1 – a round case. 80 kg, 25% TBSA. 4 × 80 × 25 = 8,000 mL in 24 hours. First 8 hours: 4,000 mL, so 8,000 ÷ 2 ÷ 8 = 500 mL/h. Next 16 hours: 8,000 ÷ 2 ÷ 16 = 250 mL/h.
Example 2 – watch the rounding. 70 kg, 30% TBSA. 4 × 70 × 30 = 8,400 mL. First 8 hours: 4,200 mL at 525 mL/h. Next 16 hours: 8,400 ÷ 2 ÷ 16 = 262.5 mL/h, which the result box rounds to 263 mL/h; the working shows the exact 262.5.
Example 3 – a small patient. 20 kg, 12% TBSA. 4 × 20 × 12 = 960 mL. First 8 hours: 480 mL at 60 mL/h. Next 16 hours: 30 mL/h. Because the weight is under 30 kg, the calculator adds a reminder: children usually also receive maintenance fluids, which this figure does not include. The paediatric maintenance fluids calculator gives that volume.
Estimating TBSA: the rule of nines
Wallace’s rule of nines gives a quick estimate of burned area in adults. For scattered burns, the patient’s palm including the fingers is roughly 1% of their body surface.
| Region (adult) | % of body surface |
|---|---|
| Head and neck | 9 |
| Each arm | 9 |
| Front of trunk | 18 |
| Back of trunk | 18 |
| Each leg | 18 |
| Perineum | 1 |
Children have a proportionally larger head and smaller legs (in an infant the head is close to 18%), so a paediatric chart such as Lund and Browder is more accurate.
Common mistakes
- Starting the clock on arrival. With a burn at 10:00 and arrival at 12:00, the first half of the volume in Example 2 (4,200 mL) has 6 hours left instead of 8: 4,200 ÷ 6 = 700 mL/h, not 525. The calculator does not make this adjustment; the IV rate calculator does the division for the time that is left.
- Including superficial burns. Red, painful skin without blisters does not count; adding it inflates the TBSA and the volume.
- Overestimating the area. Small, scattered burns are often overestimated by eye, one of the known causes of over-resuscitation.
- Treating the result as a fixed order. The figure is a starting point; the rate is adjusted to the clinical response. The fluid balance calculator helps you track what has gone in and come out.
- Forgetting other fluids. Maintenance fluids in children, and fluids given before arrival, are not part of the calculation.
Limits
The Parkland formula is an estimate based on weight and burned area alone. It does not account for inhalation injury, electrical burns, delayed resuscitation or associated trauma, all of which can change fluid needs considerably. The classic 4 mL figure is also higher than the starting point in some current protocols. Formal resuscitation formulas are generally reserved for larger burns, with thresholds that vary between guidelines. We recommend following your local burns protocol and the advice of the specialist burns service.
Frequently asked questions
What is the Parkland formula?
It estimates the crystalloid volume for the first 24 hours after a major burn: 4 mL × body weight in kg × %TBSA burned. Half is planned for the first 8 hours and the other half for the following 16 hours. For 70 kg and 30% TBSA that is 8,400 mL in total.
Do the first 8 hours start on arrival at hospital?
No. They start at the time of the burn. If a patient arrives some hours later, the first half of the volume has less time left to run, so the hourly rate for the rest of that period is higher. The calculator always repeats this point and does not adjust the rate for you.
Which burns count towards the TBSA?
Only partial-thickness and full-thickness burns (second- and third-degree). Superficial epidermal burns, such as ordinary sunburn with intact skin, are left out because they do not cause the same fluid losses. Including them inflates the TBSA and, with it, the volume.
Which fluid is used with the Parkland formula?
The original work used lactated Ringer’s solution, a balanced crystalloid equivalent to Hartmann’s. The calculator gives a volume only. The choice of fluid, and whether colloid is added later, follows your local burns protocol and the advice of the specialist burns service.
Is the Parkland result a fixed prescription?
No. It is a starting estimate. In practice the infusion is adjusted hour by hour to the patient’s response, especially urine output, and many patients end up receiving more or less than the formula suggests. It’s advisable to record the hourly urine output alongside the rate.
Can I use the Parkland formula in children?
The same calculation is used as a base, but children usually also need maintenance fluids, and TBSA is estimated with charts adapted to their body proportions. Below 30 kg the calculator shows a reminder to follow the paediatric burns protocol.
Why do some guidelines use 2 mL instead of 4 mL?
Concern about over-resuscitation, sometimes called fluid creep, has led many burns services to start between 2 and 4 mL/kg/%TBSA and titrate from there. This calculator applies the classic 4 mL figure, so its result may be higher than the starting volume in your local protocol.