# Alveolar Ventilation Calculator (VA)

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.

> Canonical page: https://elysiatools.com/en/tools/alveolar-ventilation-calculator

- **Category:** Health

- **Keywords:** alveolar ventilation, minute ventilation, tidal volume, dead space, respiratory rate, hypercapnia, hypoventilation, hyperventilation, respiratory failure, pulmonology, critical care

## 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.

## Inputs

- **Tidal Volume VT (mL)** (number): Tidal volume per breath (mL).
- **Respiratory Rate (breaths/min)** (number): Respiratory rate (breaths per minute).
- **Dead Space VD (mL, optional)** (number): Anatomical dead space per breath (mL). If omitted, estimated from body weight (~2 mL/kg).
- **Body Weight (kg, optional)** (number): Body weight (kg). Used to estimate VD (~2 mL/kg) when VD is not provided.
- **Decimal Places** (number)

## 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

- Enter tidal volume (VT) in mL and respiratory rate (RR) in breaths per minute.
- Enter dead space (VD) in mL, or provide body weight so VD can be estimated at approximately 2 mL/kg.
- The calculator applies VA = (VT − VD) × RR and converts the result from mL/min to L/min.
- The 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.

## Frequently asked questions

### What formula does the calculator use?

It uses VA = (VT − VD) × RR, where VA is alveolar ventilation, VT is tidal volume, VD is dead space, and RR is respiratory rate.

### Which inputs are required?

Tidal volume in mL and respiratory rate in breaths per minute are required.

### Can dead space be estimated?

Yes. If VD is omitted, the calculator estimates it at approximately 2 mL/kg using the entered body weight.

### What is the normal resting range?

The reference range for normal adult resting alveolar ventilation is approximately 4–6 L/min.

### Is this calculator medical advice?

No. It is an educational calculation and should not replace clinical assessment or medical advice.

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