Calculate an ideal-body-weight-based tidal-volume worksheet and compare height-based targets across common ventilation contexts.
Tidal volume (VT) is the volume of air delivered with each mechanical breath. Because lung size tracks height more closely than actual body weight, VT worksheets are usually built around ideal body weight (IBW) rather than total body mass.
This page keeps the height-based VT calculation, a simple IBW table, and an actual-weight comparison in one place so the user can see why actual body weight can overstate a starting tidal volume. It is best used as a calculation aid and documentation worksheet, not as a stand-alone ventilator management protocol.
Common reference ranges such as 4–6 mL/kg IBW for more protective ventilation and 6–8 mL/kg IBW for other settings are shown as context only. Real ventilator decisions still depend on plateau pressure, driving pressure, gas exchange, hemodynamics, the patient’s pathology, and the ICU team’s protocol.
Tidal volume has to be tied to ideal body weight, not actual weight, because lung size follows height rather than mass. This calculator keeps the height-based target, ventilator setting, and safety comparison together so the prescribed volume is easier to check before it reaches the patient.
IBW (Male) = 50 + 2.3 × (height_in − 60). IBW (Female) = 45.5 + 2.3 × (height_in − 60). Lung-Protective VT = 6 mL/kg IBW (range 4–6). Standard VT = 6–8 mL/kg IBW. Minute Ventilation = VT × RR.
Result: IBW = 70.5 kg → VT = 423 mL (6 mL/kg)
A 175 cm male has an IBW of 70.5 kg. At 6 mL/kg IBW, the target VT is 423 mL. With RR 14, minute ventilation = 5.92 L/min. If the actual weight were 100 kg, using ABW would give 700 mL — dangerously excessive.
A patient's actual weight can change substantially because of adiposity or fluid balance, but lung size does not change in parallel. That is why VT worksheets are usually based on ideal body weight derived from height.
The main value of the page is seeing the height-based VT target and how far an actual-weight estimate would drift from it. That makes it easier to document a starting point and spot obviously oversized settings.
The page does not choose the final ventilator strategy. Plateau pressure, driving pressure, pH, PaCO₂, oxygenation, and the patient’s broader physiology still determine whether a displayed VT is appropriate in practice.
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This worksheet calculates predicted body weight / ideal body weight from height and sex, then applies common lung-protective tidal-volume ranges in milliliters per kilogram of predicted body weight. It is a starting-point worksheet only; the final tidal volume still depends on plateau pressure, driving pressure, gas exchange, and the patient's broader ventilator plan.
Lung size correlates with height, not body mass. An obese and lean person of the same height have similar lung volumes. Using actual weight in obese patients causes dangerous overventilation.
Devine formula: Males: 50 + 2.3 × (height in inches − 60). Females: 45.5 + 2.3 × (height in inches − 60). Height is the only variable that changes IBW.
This page shows common lung-protective reference ranges, but the actual target has to be chosen inside the full ventilator strategy. Plateau pressure, driving pressure, gas exchange, and the patient’s overall clinical picture all matter.
Lower tidal volumes can raise PaCO₂. This page does not manage permissive hypercapnia; it only helps with the VT calculation so that the result can be reviewed in the full ventilator context.
Lower height-based tidal-volume strategies are often used more broadly than classic ARDS alone, but this page should still be treated as a calculation worksheet rather than a protocol that decides the ventilator setting by itself.
Short patients (< 150 cm) may have very low IBW. The formula still applies, but ensure VT provides adequate minute ventilation — increase RR if needed.