Burn TBSA Calculator — Rex's Toolbox

Rex says

Same equations the textbooks use — just way less awkward. Pop in your stats and I'll tell you what the number actually means for you.

Try a scenario

Click to load — tweak from there.

Inputs

Burned surface area(% TBSA)

Body weight(kg)

Formula

Hours since injury

Result

24-hour fluid volume (mL)

8,000

First 8 hours (mL)

4,000

Current rate to catch up (mL/hr)

667

Hours 8–24 rate (mL/hr)

250

Urine output target (mL/hr)

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How to use this

1Enter burned surface area (% TBSA).
2Enter body weight (kg).
3Enter formula.
4Enter hours since injury.
5Read your 24-hour fluid volume (ml) on the right — it updates as you type.
6Hit Share to keep the scenario or send it to someone.

About this calculator

Sum burned body regions using the rule of nines, then apply the Parkland formula to estimate the crystalloid volume for the first 24 hours and the first 8-hour rate.

FormulaParkland: 4 mL × kg × %TBSA, half in the first 8 hours.

Worked example

Using the values the calculator loads with:

Inputs

Burned surface area: 25 % TBSA
Body weight: 80 kg
Formula: Parkland (4 mL/kg/%)
Hours since injury: 2

Results

24-hour fluid volume (mL): 8,000
First 8 hours (mL): 4,000
Current rate to catch up (mL/hr): 667
Hours 8–24 rate (mL/hr): 250
Urine output target (mL/hr): 40

What each field means

Inputs

Burned surface area (% TBSA): The burned surface area used in the calculation, measured in % TBSA. Starts at 25 % TBSA so you have a working example on load. Accepted range: 0–100 % TBSA.
Body weight (kg): The body weight used in the calculation, measured in kg. Starts at 80 kg so you have a working example on load.
Formula: Pick the option that matches your situation — the maths changes per option. Choices: Parkland (4 mL/kg/%), Modified Brooke (2 mL/kg/%), ABA consensus (3 mL/kg/%).
Hours since injury: The hours since injury used in the calculation. Starts at 2 so you have a working example on load. Accepted range: 0–8.

Results

24-hour fluid volume (mL): Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
First 8 hours (mL): Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Current rate to catch up (mL/hr): Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Hours 8–24 rate (mL/hr): Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
Urine output target (mL/hr): Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.

FAQ

Is the clock from arrival or injury?

From the time of injury, which is why elapsed time raises the catch-up rate.

What guides titration?

Urine output, typically 0.5 mL/kg/hr in adults. The formula is a starting point, not a prescription.

Accuracy and limitations

Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.
Results do not account for medical conditions, medication, or pregnancy.
Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it.

Cite this calculator

Writing about this topic? Grab a citation — every link helps keep these tools free.

APA

RevenueLab. (2026). Burn TBSA & Fluid Resuscitation Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/burn-tbsa

HTML

<p>Source: <a href="https://www.revenuelab.fyi/toolbox/burn-tbsa" target="_blank" rel="noopener">Burn TBSA & Fluid Resuscitation Calculator — RevenueLab</a> (2026).</p>

Markdown

Source: [Burn TBSA & Fluid Resuscitation Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/burn-tbsa) (2026).