Tidal Volume Calculator
HealthCalculate predicted body weight and reference tidal volume from height and sex using the standard lung-protective ventilation formula. An educational reference, not a ventilator setting tool.
Predicted Body Weight (PBW)
61.4
Reference Tidal Volume
369
What is a Predicted Tidal Volume?
The Tidal Volume Calculator computes predicted body weight (PBW) from height and sex, then applies a reference mL-per-kg figure to estimate a lung-protective tidal volume reference value. This is an educational tool for understanding the standard height-based approach used in ventilation reference literature — not a ventilator setting tool.
For related pulmonary reference calculators, see the Lung Capacity Calculator and Vital Capacity Calculator.
How to use this Predicted Tidal Volume calculator
- Enter the height in centimetres.
- Select the sex.
- Adjust the reference tidal volume per kg (commonly 6-8 mL/kg).
- Read the Predicted Body Weight and Reference Tidal Volume instantly.
- Remember this is an educational reference only — actual ventilator settings are determined by a qualified critical care team.
Formula & Methodology
Predicted Body Weight (Male) = 50 + 2.3 × (Height in inches − 60) Predicted Body Weight (Female) = 45.5 + 2.3 × (Height in inches − 60) Reference Tidal Volume = PBW × mL/kg Worked example — a man 178 cm (70.1 in) tall, using 6 mL/kg: PBW = 50 + 2.3 × (70.1 − 60) = 50 + 23.2 = 73.2 kg Reference Tidal Volume = 73.2 × 6 = 439 mL
Frequently Asked Questions
Predicted body weight is a standardized weight estimate based on height and sex, used as the reference basis for calculating lung-protective tidal volume targets — it deliberately doesn't use actual body weight, since lung size correlates more closely with height than with weight.
Lung volume correlates much more closely with height than with actual body weight, especially in people who are overweight or underweight, so using a height-based predicted body weight avoids over- or under-estimating appropriate tidal volume for lung size.
A commonly cited lung-protective ventilation reference range is 6-8 mL per kg of predicted body weight, which is why this calculator defaults to 6 mL/kg as a starting reference point.
The calculator uses the standard formula: for men, 50 + 2.3 × (height in inches − 60); for women, 45.5 + 2.3 × (height in inches − 60), converting your entered height in centimetres to inches first.
No — this is an educational reference calculator only. Actual mechanical ventilation settings must be determined and adjusted by a qualified critical care team based on the patient's full clinical picture, not a general online calculator.
The formula reflects average physiological differences in body composition between sexes at a given height, which is why separate reference constants are used for men and women.
Yes — the calculator lets you adjust the mL/kg reference value, since different lung-protective ventilation protocols may reference slightly different target ranges within the commonly cited 6-8 mL/kg window.
The [Lung Capacity Calculator](/lung-capacity-calculator/) predicts total lung capacity from height and sex, while this calculator uses a related height-based reference (predicted body weight) specifically to estimate a lung-protective tidal volume target.
The standard predicted body weight formula used as the basis for lung-protective tidal volume targets is based on height and sex only, without an age term, reflecting its original derivation.
Tidal volume is expressed in millilitres (mL), the standard unit used in ventilator settings and respiratory physiology.
Also known as