What is the tidal volume by height?
Enter sex and height to get the predicted body weight (PBW) by the ARDS Network formula and the tidal volume at the mL per kg you choose. For information only. This is not medical advice or a diagnosis. Do not use it to make treatment decisions without a clinician. No licensed clinician has reviewed this page.
- Tidal volume
- 439
At 6 mL/kg, a predicted body weight of 73.1 kg gives a tidal volume of 439 mL.
- Predicted body weight (kg)
- 73.1
- At 4 mL/kg
- 292
- At 8 mL/kg
- 585
Tidal volume: 439. At 6 mL/kg, a predicted body weight of 73.1 kg gives a tidal volume of 439 mL.
Tidal volume in mL
This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use
How to calculate
Works out predicted body weight from height and sex with the ARDS Network formula, and the tidal volume at a chosen mL per kg of predicted body weight, with the 4 to 8 mL/kg range.
Example with the default inputs (Sex Male, Height 5 ft 10 in, Tidal volume (mL/kg) 6): At 6 mL/kg, a predicted body weight of 73.1 kg gives a tidal volume of 439 mL.
Method: PBW (kg) = 50 + 0.91 × (height cm − 152.4) for men, 45.5 + 0.91 × (height cm − 152.4) for women. Tidal volume (mL) = mL/kg × PBW.
- Predicted body weight comes from height and sex only; actual weight is not used.
- The ARDS Network trial was in adults with acute lung injury or ARDS on a ventilator. The page shows the arithmetic; it does not set a ventilator.
- Values are worked from the exact typed height and rounded once: PBW to 1 decimal and volumes to the nearest mL, halves up.
Worked examples
Each example is checked against the calculator on every build.
- Sex Male, Height 5 ft 10 in, Tidal volume (mL/kg) 6 gives Predicted body weight (kg) 73.114, Tidal volume 438.684, At 4 mL/kg 292.456, At 8 mL/kg 584.912.Source: ARDS Network 2000: PBW = 50 + 0.91 × (177.8 − 152.4) = 73.114 kg
- Sex Female, Height 5 ft 5 in, Tidal volume (mL/kg) 6 gives Predicted body weight (kg) 56.966, Tidal volume 341.796.Source: ARDS Network 2000: PBW = 45.5 + 0.91 × (165 − 152.4) = 56.966 kg
- Sex Male, Height 5 ft 0 in, Tidal volume (mL/kg) 8 gives Predicted body weight (kg) 50, Tidal volume 400, At 4 mL/kg 200, At 8 mL/kg 400.Source: ARDS Network 2000: PBW = 50 kg at 152.4 cm
- Sex Female, Height 5 ft 0 in, Tidal volume (mL/kg) 4 gives Predicted body weight (kg) 45.5, Tidal volume 182.Source: ARDS Network 2000: PBW = 45.5 kg at 152.4 cm
- Sex Male, Height 6 ft 0.8 in, Tidal volume (mL/kg) 6.5 gives Predicted body weight (kg) 79.666, Tidal volume 517.829.
Medical disclaimer
This calculator is for information and education only. It is not medical advice, and its result is not a diagnosis. Do not use it to start, stop, or change a treatment without a clinician who knows your health history. No licensed clinician has reviewed this page. This site's editors checked the formulas and worked examples against published sources. If you think you have a medical emergency, call your local emergency number.
When this does not apply. The ARDS Network trial studied adults on a ventilator with acute lung injury or ARDS. The formula is not for children or for heights under 124 cm. Other lung conditions may call for other settings.
How the volume is worked out
- Height in cm: a value typed in feet and inches or inches is × 2.54, in metres × 100.
- PBW (kg) = 50 + 0.91 × (height cm − 152.4) for men.
- PBW (kg) = 45.5 + 0.91 × (height cm − 152.4) for women.
- Tidal volume (mL) = mL/kg × PBW. The page also shows 4 and 8 mL/kg.
The arithmetic runs on the exact typed height and is rounded once: PBW to 1 decimal and volumes to the nearest mL, halves up.
Inputs: height 124 cm to 250 cm, 4 to 8 mL/kg (default 6).
Worked examples by hand
Man, 5 ft 10 in, 6 mL/kg. 70 in × 2.54 = 177.8 cm. PBW = 50 + 0.91 × 25.4 = 50 + 23.114 = 73.1 kg. 6 × 73.114 = 439 mL; 4 mL/kg 292 mL; 8 mL/kg 585 mL.
Woman, 165 cm, 6 mL/kg. PBW = 45.5 + 0.91 × 12.6 = 45.5 + 11.466 = 57.0 kg. 6 × 56.966 = 342 mL.
Man, 152.4 cm, 8 mL/kg. PBW = 50 kg; 8 × 50 = 400 mL.
Woman, 152.4 cm, 4 mL/kg. PBW = 45.5 kg; 4 × 45.5 = 182 mL.
Man, 185 cm, 6.5 mL/kg. PBW = 50 + 0.91 × 32.6 = 79.7 kg (79.666); 6.5 × 79.666 = 518 mL.
Other questions people ask
How is tidal volume worked out from height?
First the predicted body weight (PBW): 50 kg for men or 45.5 kg for women, plus 0.91 kg for each cm of height over 152.4 cm (5 ft). Then multiply by the mL per kg: at 6 mL/kg, a man 5 ft 10 in tall (PBW 73.1 kg) gets about 439 mL.
Why use predicted body weight and not actual weight?
Lung size follows height and sex, not body fat. The ARDS Network trial set tidal volume by predicted body weight, so a heavy person does not get larger breaths than their lungs can hold.
Why 6 mL/kg?
The ARDS Network trial (2000) started at 6 mL/kg of predicted body weight and found fewer deaths than with 12 mL/kg in people with acute lung injury and ARDS. The ARDS Network tools page gives tables for 4 to 8 mL/kg.
Is the inch formula the same?
The ARDS Network site also gives 50 or 45.5 + 2.3 × (height in inches − 60). That is 0.9055 kg per cm, a little less than 0.91. This page uses the centimetre form of the 2000 paper, so results can differ by a few tenths of a kg.
What heights does it accept?
124 cm to 250 cm. Martin and Richards (2017) note that the formulas are defined for heights above about 152 cm and become less valid below about 124 cm.
Does the page set a ventilator?
No. It shows the arithmetic of the formula. Ventilator settings are a clinical decision.