Ventilator Tidal Volume Calculator

Clinical disclaimer: This tool is for education and double-checking only. Ventilator settings must be chosen by qualified clinicians using local protocols and patient context.

Calculator

Sex

Used for predicted body weight (PBW).

Height unit

Enter measured height when possible.

Height value

PBW estimates lung size, not mass.

Preset

Presets update the target field.

Target (mL/kg PBW)

Common protocols use 4–8.

Rounding (mL)

Pick what your device supports.

Range low (mL/kg)

Range high (mL/kg)

Add to export history

Stores each run for CSV.

Clinical note (optional)

Exports truncate long notes.

Reset

Note: Session history is stored server-side for exports.

Example data table

Scenario	Sex	Height (cm)	PBW (kg)	Target (mL/kg)	Vt (mL)	Range 4–8 (mL)
Adult ARDS	Male	175.0	70.6	6.0	423	282–565
Post-op	Female	160.0	52.4	7.0	367	210–419
COPD exacerbation	Male	168.0	64.2	8.0	514	257–514

Examples are illustrative; follow clinical protocol.

Formula used

Predicted Body Weight (PBW)

Male: PBW = 50 + 0.91 × (Height(cm) − 152.4)
Female: PBW = 45.5 + 0.91 × (Height(cm) − 152.4)

PBW better reflects lung size than actual weight.

Tidal volume (Vt)

Vt(mL) = Target(mL/kg) × PBW(kg)

Use targets and monitoring per your unit’s guidance.

How to use this calculator

Select sex and enter the patient’s height.
Choose a preset or set a custom mL/kg target.
Pick rounding that matches ventilator increments.
Optionally set a low/high reference range.
Press Calculate to see results above the form.
Download CSV or PDF for notes and teaching.

FAQs

1) Why use predicted body weight instead of actual weight?

Actual weight can overestimate lung size, especially with obesity. PBW uses height and sex, helping keep tidal volumes aligned with lung capacity.

2) What target should I pick for ARDS?

Many ARDS protocols aim for lower tidal volumes (often around 6 mL/kg PBW) with careful monitoring. Always follow your institutional guideline.

3) Is 8 mL/kg always unsafe?

Not always. Some contexts may tolerate higher volumes, but lung-protective strategies frequently prefer lower targets. Clinical monitoring is key.

4) Does this tool account for plateau pressure?

No. Use the calculated Vt as a starting estimate, then adjust based on plateau pressure, compliance, gas exchange, and patient-ventilator interaction.

5) What if height is unknown or estimated?

Estimation can introduce meaningful error. Document the source, remeasure when possible, and reevaluate settings as more accurate data becomes available.

6) Why include a range slider inputs?

The range is a reference span computed from low/high mL/kg values you choose. It helps compare your target to a protocol window.

7) How does rounding affect results?

Rounding aligns the setpoint with typical ventilator step sizes. It may shift Vt slightly, so keep rounding modest when precision matters.

8) What do the downloads include?

The CSV includes all session calculations if enabled. The PDF exports only the most recent calculation, suitable for quick documentation.