Calculate VA = (VT − VD) × RR in L/min. VD may be supplied or estimated as ~2 mL/kg body weight. Normal resting ~4–6 L/min; low → hypercapnia, high → hypocapnia. Derived from West, LITFL, StatPearls, and Radford 1955. Not medical advice.
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Tool usage guide
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Key facts
Category
Health
Input types
number
Output type
json
Sample coverage
4
API ready
Yes
Overview
The Alveolar Ventilation Calculator estimates alveolar ventilation (VA) in L/min using VA = (VT − VD) × RR. Enter tidal volume and respiratory rate, then provide dead space or estimate it from body weight at approximately 2 mL/kg.
When to use
Estimate effective alveolar ventilation from tidal volume, dead space, and respiratory rate.
Check how changes in respiratory rate or tidal volume affect ventilation beyond dead space.
Review whether a calculated resting value is approximately within the 4–6 L/min reference range.
How it works
1Enter tidal volume (VT) in mL and respiratory rate (RR) in breaths per minute.
2Enter dead space (VD) in mL, or provide body weight so VD can be estimated at approximately 2 mL/kg.
3The calculator applies VA = (VT − VD) × RR and converts the result from mL/min to L/min.
4The result includes effective tidal volume, the dead-space source, and a ventilation category.
Use cases
Respiratory physiology study and teaching using tidal volume, dead space, and respiratory rate.
Clinical education and critical-care review of effective, rather than total, ventilation.
Comparing measured dead-space values with an approximate weight-based estimate.
Examples
1. Normal resting alveolar ventilation
Medical student
Background
A student is reviewing a resting adult example with a tidal volume of 500 mL, respiratory rate of 12 breaths/min, and dead space of 150 mL.
Problem
Calculate the effective alveolar ventilation and compare it with the approximate resting reference range.
How to use
Enter VT as 500, RR as 12, VD as 150, and choose 1 decimal place.